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| L-proline |
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| CHEBI:17203 |
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| L-proline |
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| Pyrrolidine in which the pro-S hydrogen at position 2 is substituted by a carboxylic acid group. L-Proline is the only one of the twenty DNA-encoded amino acids which has a secondary amino group α to the carboxyl group. It is an essential component of collagen and is important for proper functioning of joints and tendons. It also helps maintain and strengthen heart muscles. |
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This entity has been manually annotated by the ChEBI Team.
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CHEBI:45159, CHEBI:45100, CHEBI:45040, CHEBI:42067, CHEBI:184637, CHEBI:6286, CHEBI:13154, CHEBI:21373
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| ChemicalBook:CB8500061, eMolecules:524642, ZINC000000895360 |
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Molfile
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SDF
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more structures >>
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| Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group -NH2 but is rather a secondary amine. The secondary amine nitrogen is in the protonated form (NH2+) under biological conditions, while the carboxyl group is in the deprotonated −COO− form. The "side chain" from the α carbon connects to the nitrogen forming a pyrrolidine loop, classifying it as a aliphatic amino acid. It is non-essential in humans, meaning the body can synthesize it from the non-essential amino acid L-glutamate. It is encoded by all the codons starting with CC (CCU, CCC, CCA, and CCG).
Proline is the only proteinogenic amino acid which is a secondary amine, as the nitrogen atom is attached both to the α-carbon and to a chain of three carbons that together form a five-membered ring. |
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Read full article at Wikipedia
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| InChI=1S/C5H9NO2/c7-5(8)4-2-1-3-6-4/h4,6H,1-3H2,(H,7,8)/t4-/m0/s1 |
| ONIBWKKTOPOVIA-BYPYZUCNSA-N |
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Mus musculus
(NCBI:txid10090)
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Source: BioModels - MODEL1507180067
See:
PubMed
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Chlamydomonas reinhardtii
(NCBI:txid3055)
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See:
PubMed
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Saccharomyces cerevisiae
(NCBI:txid4932)
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Source: yeast.sf.net
See:
PubMed
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Escherichia coli
(NCBI:txid562)
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See:
PubMed
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Homo sapiens
(NCBI:txid9606)
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See:
DOI
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Homo sapiens
(NCBI:txid9606)
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Found in
blood serum
(BTO:0000133).
See:
MetaboLights Study
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Bronsted base
A molecular entity capable of accepting a hydron from a donor (Bronsted acid).
(via organic amino compound )
Bronsted acid
A molecular entity capable of donating a hydron to an acceptor (Bronsted base).
(via oxoacid )
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Escherichia coli metabolite
Any bacterial metabolite produced during a metabolic reaction in Escherichia coli.
Saccharomyces cerevisiae metabolite
Any fungal metabolite produced during a metabolic reaction in Baker's yeast (Saccharomyces cerevisiae ).
micronutrient
Any nutrient required in small quantities by organisms throughout their life in order to orchestrate a range of physiological functions.
algal metabolite
Any eukaryotic metabolite produced during a metabolic reaction in algae including unicellular organisms like chlorella and diatoms to multicellular organisms like giant kelps and brown algae.
mouse metabolite
Any mammalian metabolite produced during a metabolic reaction in a mouse (Mus musculus).
compatible osmolytes
human metabolite
Any mammalian metabolite produced during a metabolic reaction in humans (Homo sapiens).
(via proline )
Daphnia magna metabolite
A Daphnia metabolite produced by the species Daphnia magna.
(via proline )
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nutraceutical
A product in capsule, tablet or liquid form that provide essential nutrients, such as a vitamin, an essential mineral, a protein, an herb, or similar nutritional substance.
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View more via ChEBI Ontology
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(−)-(S)-proline
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NIST Chemistry WebBook
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(−)-2-pyrrolidinecarboxylic acid
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ChemIDplus
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(−)-proline
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ChemIDplus
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(2S)-pyrrolidine-2-carboxylic acid
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IUPAC
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(S)-2-carboxypyrrolidine
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DrugBank
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(S)-2-pyrrolidinecarboxylic acid
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ChemIDplus
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(S)-pyrrolidine-2-carboxylic acid
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ChEBI
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2-Pyrrolidinecarboxylic acid
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KEGG COMPOUND
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L-(−)-proline
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NIST Chemistry WebBook
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L-α-pyrrolidinecarboxylic acid
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ChemIDplus
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L-Prolin
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ChEBI
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L-Proline
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KEGG COMPOUND
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L-pyrrolidine-2-carboxylic acid
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ChemIDplus
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P
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ChEBI
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prolina
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ChemIDplus
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PROLINE
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PDBeChem
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prolinum
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ChemIDplus
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4125
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DrugCentral
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C00001388
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KNApSAcK
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C00148
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KEGG COMPOUND
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D00035
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KEGG DRUG
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DB00172
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DrugBank
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HMDB0000162
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HMDB
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L-proline
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Wikipedia
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PRO
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PDBeChem
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PRO
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MetaCyc
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| View more database links |
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147-85-3
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CAS Registry Number
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KEGG COMPOUND
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147-85-3
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CAS Registry Number
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NIST Chemistry WebBook
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147-85-3
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CAS Registry Number
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ChemIDplus
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50152
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Gmelin Registry Number
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Gmelin
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80810
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Reaxys Registry Number
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Reaxys
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Roux A, Xu Y, Heilier JF, Olivier MF, Ezan E, Tabet JC, Junot C (2012)
Annotation of the human adult urinary metabolome and metabolite identification using ultra high performance liquid chromatography coupled to a linear quadrupole ion trap-Orbitrap mass spectrometer.
Analytical chemistry 84, 6429-6437 [PubMed:22770225]
[show Abstract]
Metabolic profiles of biofluids obtained by atmospheric pressure ionization mass spectrometry-based technologies contain hundreds to thousands of features, most of them remaining unknown or at least not characterized in analytical systems. We report here on the annotation of the human adult urinary metabolome and metabolite identification from electrospray ionization mass spectrometry (ESI-MS)-based metabolomics data sets. Features of biological interest were first of all annotated using the ESI-MS database of the laboratory. They were also grouped, thanks to software tools, and annotated using public databases. Metabolite identification was achieved using two complementary approaches: (i) formal identification by matching chromatographic retention times, mass spectra, and also product ion spectra (if required) of metabolites to be characterized in biological data sets to those of reference compounds and (ii) putative identification from biological data thanks to MS/MS experiments for metabolites not available in our chemical library. By these means, 384 metabolites corresponding to 1484 annotated features (659 in negative ion mode and 825 in positive ion mode) were characterized in human urine samples. Of these metabolites, 192 and 66 were formally and putatively identified, respectively, and 54 are reported in human urine for the first time. These lists of features could be used by other laboratories to annotate their ESI-MS metabolomics data sets. | Satomura T, Hara Y, Suye S, Sakuraba H, Ohshima T (2012)
Gene expression and characterization of a third type of dye-linked L-proline dehydrogenase from the aerobic hyperthermophilic archaeon, Aeropyrum pernix.
Bioscience, biotechnology, and biochemistry 76, 589-593 [PubMed:22451406]
[show Abstract]
A third novel type of dye-linked L-proline dehydrogenase (LPDH) has recently been found in the hyperthermophilic archaeon, Pyrobaculum calidifontis, by Satomura et al. The gene encoding the enzyme homologue was identified in the aerobic hyperthermophilic archaeon, Aeropyrum pernix. The gene was successfully expressed in Escherichia coli, and the product was purified to homogeneity and characterized. The expressed enzyme was highly thermostable LPDH having a molecular mass of about 88 kDa and a homodimeric structure. The preferred substrate for the enzyme was L-proline with 2,6-dichloroindophenol (DCIP) as the electron acceptor. However, the enzyme did not utilize ferricyanide as the electron acceptor, in contrast to all other known LPDHs. The electrochemical determination of L-proline at concentrations from 0 to 0.7 mM was achieved by using A. pernix LPDH. A phylogenetic analysis revealed A. pernix LPDH to be clustered with the third type of LPDHs, and to be clearly separated from the clusters of previously known heterooligomeric LPDHs. | Zarse K, Schmeisser S, Groth M, Priebe S, Beuster G, Kuhlow D, Guthke R, Platzer M, Kahn CR, Ristow M (2012)
Impaired insulin/IGF1 signaling extends life span by promoting mitochondrial L-proline catabolism to induce a transient ROS signal.
Cell metabolism 15, 451-465 [PubMed:22482728]
[show Abstract]
Impaired insulin and IGF-1 signaling (iIIS) in C. elegans daf-2 mutants extends life span more than 2-fold. Constitutively, iIIS increases mitochondrial activity and reduces reactive oxygen species (ROS) levels. By contrast, acute impairment of daf-2 in adult C. elegans reduces glucose uptake and transiently increases ROS. Consistent with the concept of mitohormesis, this ROS signal causes an adaptive response by inducing ROS defense enzymes (SOD, catalase), culminating in ultimately reduced ROS levels despite increased mitochondrial activity. Inhibition of this ROS signal by antioxidants reduces iIIS-mediated longevity by up to 60%. Induction of the ROS signal requires AAK-2 (AMPK), while PMK-1 (p38) and SKN-1 (NRF-2) are needed for the retrograde response. IIIS upregulates mitochondrial L-proline catabolism, and impairment of the latter impairs the life span-extending capacity of iIIS while L-proline supplementation extends C. elegans life span. Taken together, iIIS promotes L-proline metabolism to generate a ROS signal for the adaptive induction of endogenous stress defense to extend life span. | Jung H, Hilger D, Raba M (2012)
The Na⁺/L-proline transporter PutP.
Frontiers in bioscience (Landmark edition) 17, 745-759 [PubMed:22201772]
[show Abstract]
The Na⁺/L-proline transporter PutP is a member of the Na⁺/solute symporter family (TC 2A.21, SLC5), which contains several hundred proteins of pro- and eukaryotic origin. Within the family, the capability of L-proline uptake is restricted to proteins of prokaryotes. PutP contributes to the use of L-proline as a nutrient. In addition, the transporter may supply cells with compatible solute during adaptation to osmotic stress. Based on these and other functions, PutP is of significance for various bacteria-host interactions including the virulence of human pathogens. A homology model of Escherichia coli PutP was generated based on the crystal structure of the Vibrio parahaemolyticus Na+/galactose symporter. According to the model, PutP has a core structure of five plus five transmembrane domains forming an inverted repeat similar as originally revealed by the crystal structure of the Na+/leucine transporter LeuT. The homology model is experimentally verified by Cys cross-linking and site-directed spin labeling in combination with electron paramagnetic resonance spectroscopy. The putative sites of Na⁺ and L-proline binding are described, and a putative transport mechanism is discussed. | Moses S, Sinner T, Zaprasis A, Stöveken N, Hoffmann T, Belitsky BR, Sonenshein AL, Bremer E (2012)
Proline utilization by Bacillus subtilis: uptake and catabolism.
Journal of bacteriology 194, 745-758 [PubMed:22139509]
[show Abstract]
L-Proline can be used by Bacillus subtilis as a sole source of carbon or nitrogen. We traced L-proline utilization genetically to the putBCP (ycgMNO) locus. The putBCP gene cluster encodes a high-affinity proline transporter (PutP) and two enzymes, the proline dehydrogenase PutB and the Δ(1)-pyrroline-5-carboxylate dehydrogenase PutC, which jointly catabolize L-proline to L-glutamate. Northern blotting, primer extension, and putB-treA reporter gene fusion analysis showed that the putBCP locus is transcribed as an L-proline-inducible operon. Its expression was mediated by a SigA-type promoter and was dependent on the proline-responsive PutR activator protein. Induction of putBCP expression was triggered by the presence of submillimolar concentrations of L-proline in the growth medium. However, the very large quantities of L-proline (up to several hundred millimolar) synthesized by B. subtilis as a stress protectant against high osmolarity did not induce putBCP transcription. Induction of putBCP transcription by external L-proline was not dependent on L-proline uptake via the substrate-inducible PutP or the osmotically inducible OpuE transporter. It was also not dependent on the chemoreceptor protein McpC required for chemotaxis toward L-proline. Our findings imply that B. subtilis can distinguish externally supplied L-proline from internal L-proline pools generated through de novo synthesis. The molecular basis of this regulatory phenomenon is not understood. However, it provides the B. subtilis cell with a means to avoid a futile cycle of de novo L-proline synthesis and consumption by not triggering the expression of the putBCP L-proline catabolic genes in response to the osmoadaptive production of the compatible solute L-proline. | Casado C, Castán J, Gracia I, Yus M, Mayoral A, Mayoral A, Sebastián V, López-Ram-de-Viu P, Uriel S, Coronas J (2012)
L- and D-proline adsorption by chiral ordered mesoporous silica.
Langmuir : the ACS journal of surfaces and colloids 28, 6638-6644 [PubMed:22475019]
[show Abstract]
Chiral ordered mesoporous silica (COMS) was synthesized in the presence of amino acid proline by combining tetraethyl orthosilicate and quaternized aminosilane silica sources. The as-prepared materials were activated by calcination or microwave chemical extraction to remove the organic templates. The powder X-ray diffraction and N2 adsorption characterization revealed in COMS the structural and textural features of MCM-41-type silica. The chirality of the material was disclosed by mixed and separate L- and D-proline adsorption on the COMS prepared with L-proline (L-Pro-COMS) and D-proline (d-Pro-COMS). It was found that the maximum L-proline and D-proline adsorption capacities on L-Pro-COMS were ca. 2.3 and 0.6 mmol/g, respectively, while the adsorption of D-proline was higher than that of l-proline on d-Pro-COMS. Finally, both activation routes yielded enantioselective silicas able to separate proline racemate. | Elnagdi NM, Al-Hokbany NS (2012)
Organocatalysis in synthesis: L-proline as an enantioselective catalyst in the synthesis of pyrans and thiopyrans.
Molecules (Basel, Switzerland) 17, 4300-4312 [PubMed:22491679]
[show Abstract]
The multicomponent reaction (MCR) of aromatic aldehydes 1 and malononitrile (2) with active methylenes 5a-h in the presence of L-proline produced pyrans and thiopyrans 6a-h stereospecifically and in good yields. Moreover a novel MCR of ethyl propiolate (8) with 1 and 2 in the presence of L-proline to afford (R)-polysubstituted pyran is also reported. X-ray structures, e.e. and optical activity of the synthesized compounds indicated that L-proline as a catalyst is responsible for the observed enantioselectivity in the studied reactions. | Lee SY, Kim YH, Min J (2009)
The effect of ArgR-DNA binding affinity on ornithine production in Corynebacterium glutamicum.
Current microbiology 59, 483-488 [PubMed:19688381]
[show Abstract]
pEMBTL-SY1, which can over produce the ArgR protein in Corynebacterium glutamicum, was constructed. The DNA-binding affinity of ArgR was analyzed using a Chromatin Immunoprecipitation (ChIP) assay. The level of ArgR protein expression in the plasmid-carrying C. glutamicum (pEMBTL-SY1) was higher than that in the wild-type strain. On the other hand, there was no increase in the DNA-binding affinity of ArgR on the upstream of argB and the level of ornithine production. The DNA-binding affinity of ArgR on the arg operon and the level of ornithine production in the presence of three metabolites, ornithine, arginine, and proline, were examined as feedback controlling effectors in the arginine biosynthesis pathway in C. glutamicum. The ChIP assay showed that the supplemented metabolites altered the ArgR-binding affinity on the upstream of argB, which is consistent with the change in ornithine production. This suggests that the regulation of ornithine biosynthesis by the transcriptional regulator, ArgR, depends on the DNA-binding affinity of the arg operon, which is regulated by the feedback controlling effectors, rather than on the level of ArgR protein expression. | Khrustalev VV (2009)
Can mutational GC-pressure create new linear B-cell epitopes in herpes simplex virus type 1 glycoprotein B?
Immunological investigations 38, 613-623 [PubMed:19811425]
[show Abstract]
We showed that GC-content of nucleotide sequences coding for linear B-cell epitopes of herpes simplex virus type 1 (HSV1) glycoprotein B (gB) is higher than GC-content of sequences coding for epitope-free regions of this glycoprotein (G + C = 73 and 64%, respectively). Linear B-cell epitopes have been predicted in HSV1 gB by BepiPred algorithm ( www.cbs.dtu.dk/services/BepiPred ). Proline is an acrophilic amino acid residue (it is usually situated on the surface of protein globules, and so included in linear B-cell epitopes). Indeed, the level of proline is much higher in predicted epitopes of gB than in epitope-free regions (17.8% versus 1.8%). This amino acid is coded by GC-rich codons (CCX) that can be produced due to nucleotide substitutions caused by mutational GC-pressure. GC-pressure will also lead to disappearance of acrophobic phenylalanine, isoleucine, methionine and tyrosine coded by GC-poor codons. Results of our "in-silico directed mutagenesis" showed that single nonsynonymous substitutions in AT to GC direction in two long epitope-free regions of gB will cause formation of new linear epitopes or elongation of previously existing epitopes flanking these regions in 25% of 539 possible cases. The calculations of GC-content and amino acid content have been performed by CodonChanges algorithm ( www.barkovsky.hotmail.ru ). | Loiret FG, Grimm B, Hajirezaei MR, Kleiner D, Ortega E (2009)
Inoculation of sugarcane with Pantoea sp. increases amino acid contents in shoot tissues; serine, alanine, glutamine and asparagine permit concomitantly ammonium excretion and nitrogenase activity of the bacterium.
Journal of plant physiology 166, 1152-1161 [PubMed:19215998]
[show Abstract]
Pantoea sp. is an endophytic nitrogen-fixing bacterium isolated from sugarcane tissues. The aim of the present study was to determine the contents of amino acids in sugarcane as a result of inoculation of nodes and nodal roots with Pantoea sp. strain 9C and to evaluate the effects of amino acids on growth, nitrogenase activity and ammonium excretion of the bacterium. Content of almost all amino acids increased in 30-day-old plantlets by root inoculation. The most abundant amino acids in shoot tissues were asparagine and proline, and those in nodal roots were asparagine, proline, aspartic acid, glutamic acid and serine. The bacterium was able to grow on all tested amino acids except histidine, isoleucine and leucine. Nitrogenase Pantoea sp. was partially inhibited by 1, 2 or 5mmolL(-1) and completely inhibited by 10mmolL(-1) of NH(4)(+) in the media. Pantoea sp. showed nitrogenase activity in 5mmolL(-1) of serine, asparagine, threonine, alanine, proline, tyrosine, valine, methionine, lysine, phenylalanine, cysteine, tryptophan, citrulline and ornithine. Pantoea sp. did not excrete ammonium when it grew in vivo conditions favoring nitrogen fixation; however, ammonium was detected in the supernatant when 5mmolL(-1) asparagine, aspartic acid, alanine, serine or glutamine was added to the medium. The highest ammonium concentration in the supernatant was detected, when Pantoea grew on serine. Ammonium in the supernatant and nitrogenase activity were only detectable concomitantly when the medium was supplemented with serine, alanine, glutamine or asparagine. We discuss roles of amino acids on plant-bacteria interaction during the colonization of sugarcane plants. | Forster M, Dyer MS, Persson M, Raval R (2009)
Probing conformers and adsorption footprints at the single-molecule level in a highly organized amino acid assembly of (S)-proline on Cu(110).
Journal of the American Chemical Society 131, 10173-10181 [PubMed:19580280]
[show Abstract]
Establishing the nanoscale details of organized amino acid assemblies at surfaces is a major challenge in the field of organic-inorganic interfaces. Here, we show that the dense (4 x 2) overlayer of the amino acid, (S)-proline on a Cu(110) surface can be explored at the single-molecule level by scanning tunneling microscopy (STM), reflection absorption infrared spectroscopy (RAIRS), and periodic density functional theory (DFT) calculations. The combination of experiment and theory, allied with the unique structural rigidity of proline, enables the individual conformers and adsorption footprints adopted within the organized assembly to be determined. Periodic DFT calculations find two energetically favorable molecular conformations, projecting mirror-image chiral adsorption footprints at the surface. These two forms can be experimentally distinguished since the positioning of the amino group within the pyrrolidine ring leads each chiral footprint and associated conformer to adopt very different ring orientations, producing distinct contrasts in the STM images. DFT modeling shows that the two conformers can generate eight possible (4 x 2) overlayers with a variety of adsorption footprint arrangements. STM images simulated for each structural model enables a direct comparison to be made with the experiment and narrows the (4 x 2) overlayer to one specific structural model in which the juxtaposition of molecules leads to the formation of one-dimensional hydrogen bonded prolate chains directed along the [110] direction. | Cañas RA, Quilleré I, Christ A, Hirel B (2009)
Nitrogen metabolism in the developing ear of maize (Zea mays): analysis of two lines contrasting in their mode of nitrogen management.
The New phytologist 184, 340-352 [PubMed:19656302]
[show Abstract]
*The main steps of nitrogen (N) metabolism were characterized in the developing ear of the two maize (Zea mays) lines F2 and Io, which were previously used to investigate the genetic basis of nitrogen use efficiency (NUE) in relation to yield. *During the grain-filling period, we monitored changes in metabolite content, enzyme activities and steady-state levels of transcripts for marker genes of amino acid synthesis and interconversion in the cob and the kernels. *Under low N fertilization conditions, line Io accumulated glutamine, asparagine and alanine preferentially in the developing kernels, whereas in line F2, glutamine and proline were the predominant amino acids. Quantification of the mRNA-encoding enzymes involved in asparagine, alanine and proline biosynthesis confirmed that the differences observed between the two lines at the physiological level are likely to be attributable to enhanced expression of the cognate genes. *Integrative analysis of physiological and gene expression data indicated that the developing ear of line Io had higher N use and transport capacities than line F2. Thus, in maize there is genetic and environmental control of N metabolism not only in vegetative source organs but also in reproductive sink organs. | Takagi H (2008)
Proline as a stress protectant in yeast: physiological functions, metabolic regulations, and biotechnological applications.
Applied microbiology and biotechnology 81, 211-223 [PubMed:18802692]
[show Abstract]
Proline is an important amino acid in terms of its biological functions and biotechnological applications. In response to osmotic stress, proline is accumulated in many bacterial and plant cells as an osmoprotectant. However, it has been shown that proline levels are not increased under various stress conditions in the yeast Saccharomyces cerevisiae cells. Proline is believed to serve multiple functions in vitro such as protein and membrane stabilization, lowering the T (m) of DNA, and scavenging of reactive oxygen species, but the mechanisms of these functions in vivo are poorly understood. Yeast cells biosynthesize proline from glutamate in the cytoplasm via the same pathway found in bacteria and plants and also convert excess proline to glutamate in the mitochondria. Based on the fact that proline has stress-protective activity, S. cerevisiae cells that accumulate proline were constructed by disrupting the PUT1 gene involved in the degradation pathway and by expressing the mutant PRO1 gene encoding the feedback inhibition-less sensitive gamma-glutamate kinase to enhance the biosynthetic activity. The engineered yeast strains successfully showed enhanced tolerance to many stresses, including freezing, desiccation, oxidation, and ethanol. However, the appropriate cellular level and localization of proline play pivotal roles in the stress-protective effect. These results indicate that the increased stress protection is observed in yeast cells under the artificial condition of proline accumulation. Proline is expected to contribute to yeast-based industries by improving the production of frozen dough and alcoholic beverages or breakthroughs in bioethanol production. | Rebane R, Herodes K (2008)
Evaluation of the botanical origin of estonian uni- and polyfloral honeys by amino acid content.
Journal of agricultural and food chemistry 56, 10716-10720 [PubMed:18973300]
[show Abstract]
The free amino acid content of 61 honey samples from Estonia has been determined by HPLC-UV with precolumn derivatization with diethyl ethoxymethylenemalonate. Analyzed samples were seven types of unifloral honeys and polyfloral honeys. The main amino acids found in Estonian honeys were proline and phenylalanine. The resulting data have been analyzed by t test and principal component analysis (PCA). t Test revealed that some amino acids (alpha-alanine, beta-alanine, asparagine, gamma-aminobutyric acid, glutamine, glycine, histidine, ornithine, phenylalanine, proline, serine, and tryptophan) are more potent for assigning honey botanical origin than others. PCA enabled differentiation of some honey types by their botanical origin. In the space of the two first principal components, heather honeys form a cluster that is clearly separable from, for example, polyfloral honeys. It is concluded that analysis of the free amino acid profile may serve as a useful tool to assess the botanical origin of Estonian honeys. | Harrigan GG, Stork LG, Riordan SG, Reynolds TL, Ridley WP, Masucci JD, Macisaac S, Halls SC, Orth R, Smith RG, Wen L, Brown WE, Welsch M, Riley R, McFarland D, Pandravada A, Glenn KC (2007)
Impact of genetics and environment on nutritional and metabolite components of maize grain.
Journal of agricultural and food chemistry 55, 6177-6185 [PubMed:17608428]
[show Abstract]
The Organization for Economic Co-operation and Development (OECD) recommends the measurement of specific plant components for compositional assessments of new biotechnology-derived crops. These components include proximates, nutrients, antinutrients, and certain crop-specific secondary metabolites. A considerable literature on the natural variability of these components in conventional and biotechnology-derived crops now exists. Yet the OECD consensus also suggests measurements of any metabolites that may be directly associated with a newly introduced trait. Therefore, steps have been initiated to assess natural variation in metabolites not typically included in the OECD consensus but which might reasonably be expected to be affected by new traits addressing, for example, nutritional enhancement or improved stress tolerance. The compositional study reported here extended across a diverse genetic range of maize hybrids derived from 48 inbreds crossed against two different testers. These were grown at three different, but geographically similar, locations in the United States. In addition to OECD analytes such as proximates, total amino acids and free fatty acids, the levels of free amino acids, sugars, organic acids, and selected stress metabolites in harvested grain were assessed. The major free amino acids identified were asparagine, aspartate, glutamate, and proline. The major sugars were sucrose, glucose, and fructose. The most predominant organic acid was citric acid, with only minor amounts of other organic acids detected. The impact of genetic background and location was assessed for all components. Overall, natural variation in free amino acids, sugars, and organic acids appeared to be markedly higher than that observed for the OECD analytes. | Bosch L, Alegría A, Farré R (2006)
Amino acid contents of infant foods.
International journal of food sciences and nutrition 57, 212-218 [PubMed:17127472]
[show Abstract]
The protein quality of three milk-cereal-based infant foods (paps) was evaluated by determining their amino acid contents and calculating the amino acid score. Proteins were subjected to acid hydrolysis, prior to which cysteine and methionine were oxidized with performic acid. Amino acids were determined by reverse-phase high-performance liquid chromatography with fluorescence detection with a prior derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. Tryptophan was determined by reverse-phase high-performance liquid chromatography with ultraviolet detection after basic hydrolysis. Glutamic acid, proline and leucine were the most abundant amino acids, whereas tryptophan and cysteine had the lowest contents. Tryptophan was the limiting amino acid in the analyzed infant foods. A pap serving (250 ml) contributes significantly to fulfillment of the recommended dietary allowances of essential and semi-essential amino acids for infants (7-12 months old) and young children (1-3 years old). | Pielak GJ (2006)
Woes of proline: a cautionary kinetic tale.
Protein science : a publication of the Protein Society 15, 393-394 [PubMed:16501220] | Mayadunne R, Nguyen TT, Marriott PJ (2005)
Amino acid analysis by using comprehensive two-dimensional gas chromatography.
Analytical and bioanalytical chemistry 382, 836-847 [PubMed:15838615]
[show Abstract]
The separation characteristics of alkylchloroformate-derivatised amino acids (AAs) by using comprehensive two-dimensional gas chromatography (GCxGC) is reported. The use of a low-polarity/polar column set did not provide as good a separation performance as that achieved with a polar/non-polar column set, where the latter appeared to provide less correlation over the separation space. The degree of component correlation in each column set was estimated by using the correlation coefficient (r(2); for (1)t(R) and (2)t(R) data) with the low-polarity/polar and polar/low-polarity sets returning correlation coefficients of 0.86, and 0.00 respectively, under the respective conditions employed for the experiments. The 1.5-m non-polar (2)D column (0.1-mm ID; 0.1-mum film thickness) gave peak halfwidths of the order of 50-80 ms. Linearity of detection was good, over a three order of magnitude concentration range, with typical lower detection limit of ca. 0.01 mg L(-1), compared with 0.5 mg L(-1) for normal GC operation with splitless injection. The method was demonstrated for analysis of AAs in a range of food and beverage products, including wine, beer and honey. The major AA in these samples was proline. The Heineken beer sample had a relatively more complex and more abundant AA content compared with the other beer sample. The wine and honey samples also gave a range of AA compounds. Repetition of the sample preparation/analysis procedure for the honey sample gave acceptable reproducibility for individual AAs. | Wu G, Bazer FW, Hu J, Johnson GA, Spencer TE (2005)
Polyamine synthesis from proline in the developing porcine placenta.
Biology of reproduction 72, 842-850 [PubMed:15576824]
[show Abstract]
Polyamines (putrescine, spermidine, and spermine) are essential for placental growth and angiogenesis. However, little is known about polyamine synthesis in the porcine placenta during conceptus development. The present study was conducted to test the hypothesis that arginine and proline are the major sources of ornithine for placental polyamine production in pigs. Placentae, amniotic fluid, and allantoic fluid were obtained from gilts on Days 20, 30, 35, 40, 45, 50, 60, 90, and 110 of the 114-day gestation (n = 6 per day). Placentae as well as amniotic and allantoic fluids were analyzed for arginase, proline oxidase, ornithine aminotransferase (OAT), ornithine decarboxylase (ODC), proline transport, concentrations of amino acids and polyamines, and polyamine synthesis using established radiochemical and chromatographic methods. Neither arginase activity nor conversion of arginine into polyamines was detected in the porcine placenta. In contrast, both proline and ornithine were converted into putrescine, spermidine, and spermine in placental tissue throughout pregnancy. The activities of proline oxidase, OAT, and ODC as well as proline transport, polyamine synthesis from proline, and polyamine concentrations increased markedly between Days 20 and 40 of gestation, declined between Days 40 and 90 of gestation, and remained at the reduced level through Day 110 of gestation. Proline oxidase and OAT, but not arginase, were present in allantoic and amniotic fluids for the production of ornithine (the immediate substrate for polyamine synthesis). The activities of these two enzymes as well as the concentrations of ornithine and total polyamines in fetal fluids were highest at Day 40 but lowest at Days 20, 90, and 110 of gestation. These results indicate that proline is the major amino acid for polyamine synthesis in the porcine placenta and that the activity of this synthetic pathway is maximal during early pregnancy, when placental growth is most rapid. Our novel findings provide a new base of information for future studies to define the role of proline in fetoplacental growth and development. | Omura F, Fujita A, Miyajima K, Fukui N (2005)
Engineering of yeast Put4 permease and its application to lager yeast for efficient proline assimilation.
Bioscience, biotechnology, and biochemistry 69, 1162-1171 [PubMed:15973048]
[show Abstract]
The Saccharomyces cerevisiae Put4 permease is significant for the transport of proline, alanine, and glycine. Put4p downregulation is counteracted by npi1 mutation that affects the cellular ubiquitination function. Here we describe mutant Put4 permeases, in which up to nine lysine residues in the cytoplasmic N-terminal domain have been replaced by arginine. The steady-state protein level of the mutant permease Put4-20p (Lys9, Lys34, Lys35, Lys60, Lys68, Lys71, Lys93, Lys105, Lys107 --> Arg) was largely higher compared to that of the wild-type Put4p, indicating that the N-terminal lysines can undergo ubiquitination and the subsequent degradation steps. Proline is the only amino acid that yeast assimilates with difficulty under standard brewing conditions. A lager yeast strain provided with Put4-20p was able to assimilate proline efficiently during beer fermentations. These results suggest possible industrial applications of the mutant Put4 permeases in improved fermentation systems for beer and other alcoholic beverages based on proline-rich fermentable sources. | Stone A, Ratnasinghe LD, Emerson GL, Modali R, Lehman T, Runnells G, Carroll A, Carter W, Barnhart S, Rasheed AA, Greene G, Johnson DE, Ambrosone CB, Kadlubar FF, Lang NP (2005)
CYP3A43 Pro(340)Ala polymorphism and prostate cancer risk in African Americans and Caucasians.
Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology 14, 1257-1261 [PubMed:15894682]
[show Abstract]
The human cytochrome P450 3A subfamily of enzymes is involved in the metabolism of steroid hormones, carcinogens, and many drugs. A cytosine-to-guanine polymorphism in CYP3A43 results in a proline-to-alanine substitution at codon 340. Although the functional significance of this polymorphism is unknown, we postulate that the substitution of proline, an alpha-imino acid, with alanine, an amino acid, could be of biochemical significance. In a case-control study with 490 incident prostate cancer cases (124 African Americans and 358 Caucasians) and 494 controls (167 African Americans and 319 Caucasians), we examined the association between CYP3A43 Pro(340)Ala polymorphism and prostate cancer risk. When all subjects were considered, there was a 3-fold increase in risk of prostate cancer among individuals with the CYP3A43-Ala/Ala genotype (odds ratio, 3.0; 95% confidence interval, 1.2-7.2) compared with those with the CYP3A43-Pro/Pro genotype after adjusting for age, race, and smoking. The prevalence of the polymorphism was significantly higher in African Americans than Caucasians (45% versus 13%). In African Americans, there was a 2.6-fold increase in prostate cancer risk among individuals with the CYP3A43-Ala/Ala genotype (odds ratio, 2.6; 95% confidence interval, 1.0-7.0) compared with those with the CYP3A43-Pro/Pro genotype. Among Caucasians, the small number of homozygotes precluded computing risk estimates; there were only three individuals with the CYP3A43-Ala/Ala genotype. Our results suggest that the CYP3A43-Pro(340)Ala polymorphism contributes to prostate cancer risk. | Samaras TS, Camburn PA, Chandra SX, Gordon MH, Ames JM (2005)
Antioxidant properties of kilned and roasted malts.
Journal of agricultural and food chemistry 53, 8068-8074 [PubMed:16190672]
[show Abstract]
Compounds possessing antioxidant activity play a crucial role in delaying or preventing lipid oxidation in foods and beverages during processing and storage. Such reactions lead to loss of product quality, especially as a consequence of off-flavor formation. The aim of this study was to determine the antioxidant activity of kilned (standard) and roasted (speciality) malts in relation to phenolic compounds, sugars, amino acids, and color [assessed as European Brewing Convention units (degrees EBC) and absorbance at 420 nm]. The concentrations of sugars and amino acids decreased with the intensity of the applied heat treatment, and this was attributed to the extent of the Maillard reaction, as well as sugar caramelization, in the highly roasted malts. Proline, followed by glutamine, was the most abundant free amino/imino acid in the malt samples, except those that were highly roasted, and maltose was the most abundant sugar in all malts. Levels of total phenolic compounds decreased with heat treatment. Catechin and ferulic acid were the most abundant phenolic compounds in the majority of the malts, and amounts were highest in the kilned samples. In highly roasted malts, degradation products of ferulic acid were identified. Antioxidant activity increased with the intensity of heating, in parallel with color formation, and was significantly higher for roasted malts compared to kilned malts. In kilned malts, phenolic compounds were the main identified contributors to antioxidant activity, with Maillard reaction products also playing a role. In roasted malts, Maillard reaction products were responsible for the majority of the antioxidant activity. | Chen W, Kahrizi K, Meyer NC, Riazalhosseini Y, Van Camp G, Najmabadi H, Smith RJ (2005)
Mutation of COL11A2 causes autosomal recessive non-syndromic hearing loss at the DFNB53 locus.
Journal of medical genetics 42, e61 [PubMed:16033917]
[show Abstract]
BackgroundAllele variants of COL11A2, encoding collagen type XI alpha2, cause autosomal dominant non-syndromic hearing loss (ARNSHL) at the DFNA13 locus (MIM 601868) and various syndromes that include a deafness phenotype.ObjectiveTo describe a genome-wide scan carried out on a consanguineous Iranian family segregating ARNSHL.ResultsGenotyping data identified a novel locus for ARNSHL on chromosome 6p21.3, which was designated DFNB53. Homozygosity for the P621T mutation of COL11A2 was present in all deaf persons in this family; this same variation was absent in 269 Iranian controls. Sequence comparison of collagen type XI alpha1 and alpha2 peptides across species shows that the replaced proline is an evolutionarily conserved amino acid.ConclusionsThe P621T mutation of COL11A2 affects the Y position of the canonical -Gly-X-Y- repeat in collagens. It lies near the amino-terminus of the triple helical region and causes ARNSHL. This finding suggests that mutation type and location are critical determinants in defining the phenotype of COL11A2 associated diseases. | Goldstrohm DA, Pennington JE, Wells MA (2003)
The role of hemolymph proline as a nitrogen sink during blood meal digestion by the mosquito Aedes aegypti.
Journal of insect physiology 49, 115-121 [PubMed:12770004]
[show Abstract]
Mosquitoes utilize the amino acids derived from blood meal protein to produce egg proteins. But the amino acids can also be used to produce egg lipid or can be oxidized for energy production. These latter two processes result in the release of nitrogen as toxic ammonia. Therefore, amino acids must be processed in such a way that amino acid nitrogen can be incorporated into non-toxic waste products. Proline is the predominant amino acid in the hemolymph of the adult female mosquito Aedes aegypti. After feeding on albumin meal, hemolymph proline levels increased five-fold over unfed levels, reached maximal levels in the first hours after feeding and remained high through oviposition. Hemolymph proline levels increased as the concentration of protein in the meal increased. When starved of sugar for 24 h prior to feeding on an albumin meal, hemolymph proline levels increased four-fold over the proline levels of non-starved mosquitoes. Proline levels after feeding on a protein deficient in essential amino acids, pike parvalbumin, increased to twice the levels of albumin fed mosquitoes. Based on these observations, we propose that mosquitoes utilize proline as a temporary nitrogen sink to store ammonia arising from deamination of blood meal amino acid. | Xu Y, Wu J, Pei J, Shi Y, Ji Y, Tong Q (2000)
Solution structure of BmP02, a new potassium channel blocker from the venom of the Chinese scorpion Buthus martensi Karsch.
Biochemistry 39, 13669-13675 [PubMed:11076505]
[show Abstract]
BmP02 is a 28-amino acid residue peptide purified from the venom of the Chinese scorpion Buthus martensi Karsch, which had been demonstrated to be a weak blocker of apamin-sensitive calcium-activated potassium channels. Two-dimensional NMR spectroscopy techniques were used to determine the solution structure of BmP02. The results show that BmP02 formed a alpha/beta scorpion fold, the typical three-dimensional structure adopted by most short chain scorpion toxins whose structures have been determined. However, in BmP02 this alpha/beta fold was largely distorted. The alpha-helix was shortened to only one turn, and the loop connecting the helix to the first beta-strand exhibited conformational heterogeneity. The instability of BmP02 could be attributed to a proline at position 17, which is usually a glycine. Because the residue at this position makes intense contact with the alpha-helix, it was supposed that the bulky side chain of proline had pushed the helix away from the beta-sheet. This had a significant influence on the structure and function of BmP02. The alpha-helix rotated by about 40 degrees to avoid Pro17 while forming two disulfides with the second beta-strand. The rotation further caused both ends of the helix to be unwound due to covalent restrictions. According to its structure, BmP02 was supposed to interact with its target via the side chains of Lys11 and Lys13. | Fougère F, Le Rudulier D, Streeter JG (1991)
Effects of Salt Stress on Amino Acid, Organic Acid, and Carbohydrate Composition of Roots, Bacteroids, and Cytosol of Alfalfa (Medicago sativa L.).
Plant physiology 96, 1228-1236 [PubMed:16668324]
[show Abstract]
Ethanol-soluble organic acid, carbohydrate, and amino acid constituents of alfalfa (Medicago sativa) roots and nodules (cytosol and bacteroids) have been identified by gas-liquid chromatography and high performance liquid chromatography. Among organic acids, citrate was the predominant compound in roots and cytosol, with malonate present in the highest concentration in bacteroids. These two organic acids together with malate and succinate accounted for more than 85% of the organic acid pool in nodules and for 97% in roots. The major carbohydrates in roots, nodule cytosol, and bacteroids were (descending order of concentration): sucrose, pinitol, glucose, and ononitol. Maltose and trehalose appeared to be present in very low concentrations. Asparagine, glutamate, alanine, gamma-aminobutyrate, and proline were the major amino acids in cytosol and bacteroids. In addition to these solutes, serine and glutamine were well represented in roots. When alfalfa plants were subjected to 0.15 m sodium chloride stress for 2 weeks, total organic acid concentration in nodules and roots were depressed by more than 40%, whereas lactate concentration increased by 11, 27, and 94% in cytosol, roots, and bacteroids, respectively. In bacteroids, lactate became the most abundant organic acid and might contribute partly to the osmotic adjustment. On the other hand, salt stress induced a large increase in the amino acid and carbohydrate pools. Within the amino acids, proline showed the largest increase, 11.3-, 12.8-, and 8.0-fold in roots, cytosol, and bacteroids, respectively. Its accumulation reflected an osmoregulatory mechanism not only in roots but also in nodule tissue. In parallel, asparagine concentration was greatly enhanced; this amide remained the major nitrogen solute and, in bacteroids, played a significant role in osmoregulation. On the contrary, the salt treatment had a very limited effect on the concentration of other amino acids. Among carbohydrates, pinitol concentration was increased significantly, especially in cytosol and bacteroids (5.4- and 3.4-fold, respectively), in which this cyclitol accounted for more than 35% of the total carbohydrate pool; pinitol might contribute to the tolerance to salt stress. However, trehalose concentration remained low in both nodules and roots; its role in osmoregulation appeared unlikely in alfalfa. | Newton RJ, Sen S, Puryear JD (1986)
Free proline changes in Pinus taeda L. callus in response to drought stress.
Tree physiology 1, 325-332 [PubMed:14975886]
[show Abstract]
The amino acid, proline (PRO), may have an important role in plant adaptation to drought stress. To study the effect of drought stress on PRO content of pine tissues, we measured free PRO by high pressure liquid chromatography in control ( -0.4 MPa) and drought-stressed ( -0.8, -1.0, -1.3, -1.6 MPa) callus tissue of Pinus taeda L. after eight weeks of growth. Drought stress was induced by adding polyethylene glycol (PEG) to the nutrient media. The relation between PRO accumulation and water potential was influenced by composition of the medium and temperature. Callus growing in media with water potentials of -0.8 MPa showed no increase in PRO compared to control callus in media at -0.4 MPa. When callus tissue was subjected to low water potentials (-1.6 MPa), endogenous PRO concentration increased 40-fold, while callus fresh weight decreased by more than 90%. When exogenous PRO was added to the nutrient media, endogenous PRO was directly proportional to the exogenous PRO concentration rather than reduction in callus growth. Thus low water potential in callus results in endogenous PRO accumulation and large reductions in callus fresh weight growth. Proline accumulation in pine cells appears to be related to mechanisms associated with tolerance to desiccation. | Rancourt DE, Stephenson JT, Vickell GA, Wood JM (1984)
Proline excretion by Escherichia coli K12.
Biotechnology and bioengineering 26, 74-80 [PubMed:18551589]
[show Abstract]
Proline excretion from proline overproducing strains of E. coli K12 has been studied as a model chemical production system. We have isolated proline overproducing mutants of E. coli and have shown that uncontrolled synthesis is not sufficient to cause excretion of this amino acid. An episomal mutation causing proline over production has been introduced into a series of otherwise isogenic strains that bear well defined, chromosomal lesions affecting the active uptake and catabolism of L-proline. A syntropism test reveals that L-proline is excreted by overproducing strains only if transport and/or catabolism are impaired. Dansyl derivatization and chromatographic analysis of culture supernatants shows that proline is the only amino acid excreted. Batch cultures of an excreting strain in an amino acid production medium yield culture supernatants containing 1 g proline/L, whereas no proline is detectable in supernatants derived from cultures of an overproducing strain with normal transport and catabolic activities. These data reveal that genetic lesions eliminating active uptake can be used to specifically enhance metabolite excretion. | Pringle RB (1971)
Amino Acid Composition of the Host-specific Toxin of Helminthosporium carbonum.
Plant physiology 48, 756-759 [PubMed:16657874]
[show Abstract]
The host-specific toxin of Helminthosporium carbonum (C(32)H(50)N(6)O(10)) was hydrolyzed by 6 n HCl to yield a number of alpha-amino acids. The common amino acids, proline and alanine, occurred in a ratio of 1:2. Two other unstable alpha-amino acids that produced lower color values with ninhydrin were also produced. One of these was tentatively identified as 2-amino-2,3-dehydro-3-methylpentanoic acid by electrolytic reduction to isoleucine. Additional ninhydrin-reacting substances were produced in low yield and probably represented secondary hydrolysis products of the unstable amino acids. The finding of an alpha,beta-unsaturated linkage in H. carbonum toxin explains the instability of the compound and may also account for its specific toxicity. | Thompson JF, Stewart CR, Morris CJ (1966)
Changes in amino Acid content of excised leaves during incubation I. The effect of water content of leaves and atmospheric oxygen level.
Plant physiology 41, 1578-1584 [PubMed:16656443]
[show Abstract]
Excised leaves were incubated at various water contents to determine the effect of water status on amino acid composition. Considerable proteolysis took place during incubation with a resultant increase in each amino acid in the non-protein fraction. However, serine, proline, gamma-aminobutyric acid and methyleysteine sulfoxide were the only amino acids in which there was an accumulation (i.e., net synthesis). Serine showed a small but consistent accumulation lasting for 6 days. Proline showed a greater accumulation but this ceased after 2 days.To learn more about the control of the proline accumulation during wilting, turgid and wilted leaves were incubated under aerobic and anaerobic conditions. The amino acid analyses showed that turgid leaves did not accumulate proline and that proline and methylcysteine sulfoxide accumulation was abolished by anaerobiosis. With other amino acids, relative concentration changes between wilted and non-wilted leaves were less striking than the difference between aerobic and anaerobic conditions.Under anaerobic conditions there was an increase in alanine and a large increase in gamma-aminobutyric acid which were not evident in air. Serine, aspartic acid, glutamic acid, and glutamine disappeared more rapidly and glycine disappeared less rapidly under anaerobic than under aerobic conditions.On the basis of these results, several pathways of amino acid degradation were suggested. |
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