Rhea - reaction knowledgebase

Enzymes

UniProtKB ^help_outline	7 proteins
Enzyme class ^help_outline	EC 2.4.1.22 lactose synthase
GO Molecular Function ^help_outline	GO:0004461 lactose synthase activity

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Name ^help_outline UDP-α-D-galactose Identifier CHEBI:66914 Charge -2 Formula C15H22N2O17P2 InChIKey^help_outline HSCJRCZFDFQWRP-ABVWGUQPSA-L SMILES^help_outline OC[C@H]1O[C@H](OP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2ccc(=O)[nH]c2=O)[C@H](O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 109 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline D-glucose Identifier CHEBI:4167 (CAS: 2280-44-6) ^help_outline Charge 0 Formula C6H12O6 InChIKey^help_outline WQZGKKKJIJFFOK-GASJEMHNSA-N SMILES^help_outline OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 162 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline lactose Identifier CHEBI:17716 (CAS: 63-42-3) ^help_outline Charge 0 Formula C12H22O11 InChIKey^help_outline GUBGYTABKSRVRQ-QKKXKWKRSA-N SMILES^help_outline OC[C@H]1O[C@@H](O[C@H]2[C@H](O)[C@@H](O)C(O)O[C@@H]2CO)[C@H](O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 11 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline UDP Identifier CHEBI:58223 Charge -3 Formula C9H11N2O12P2 InChIKey^help_outline XCCTYIAWTASOJW-XVFCMESISA-K SMILES^help_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 611 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline H⁺ Identifier CHEBI:15378 Charge 1 Formula H InChIKey^help_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILES^help_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,717 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule

Cross-references

	RHEA:12404	RHEA:12405	RHEA:12406	RHEA:12407
Reaction direction	undefined	left-to-right	right-to-left	bidirectional
UniProtKB ^help_outline	7 proteins	7 proteins
EC numbers ^help_outline	2.4.1.22
Gene Ontology ^help_outline	GO:0004461
KEGG ^help_outline				R00503
MetaCyc ^help_outline		LACTOSE-SYNTHASE-RXN

Publications

Alpha-lactalbumin and the lactose synthetase reaction.

Fitzgerald D.K., Brodbeck U., Kiyosawa I., Mawal R., Colvin B., Ebner K.E.

J Biol Chem 245:2103-2108(1970) [PubMed] [EuropePMC]
High-throughput mass-spectrometry monitoring for multisubstrate enzymes: determining the kinetic parameters and catalytic activities of glycosyltransferases.

Yang M., Brazier M., Edwards R., Davis B.G.

A novel high-throughput screening (HTS) method with electrospray time-of-flight (ESI-TOF) mass spectrometry allows i) rapid and broad screening of multisubstrate enzyme catalytic activity towards a range of donor and acceptor substrates; ii) determination of full multisubstrate kinetic parameters ... >> More

A novel high-throughput screening (HTS) method with electrospray time-of-flight (ESI-TOF) mass spectrometry allows i) rapid and broad screening of multisubstrate enzyme catalytic activity towards a range of donor and acceptor substrates; ii) determination of full multisubstrate kinetic parameters and the binding order of substrates. Two representative glycosyltransferases (GTs, one common, one recently isolated, one O-glycosyltransferase (O-GT), one N-glycosyltransferase (N-GT)) have been used to validate this system: the widely used bovine beta-1,4-galactosyltransferase (EC 2.4.1.22), and the recently isolated Arabidopsis thaliana GT UGT72B1 (EC 2.4.1.-). The GAR (green/amber/red) broad-substrate-specificity screen, which is based on the mass ion abundance of product, provides a fast, high-throughput method for finding potential donors and acceptors from substrate libraries. This was evaluated by using six natural and non-natural donors (alpha-UDP-D-Glucose (UDPGlc), alpha-UDP-N-Acetyl-D-glucosamine (UDPGlcNAc), alpha-UDP-D-5-thioglucose (UDP5SGlc), alpha-GDP-L-fucose (GDPFuc), alpha-GDP-D-mannose (GDPMan), alpha,beta-UDP-D-mannose (UDPMan)) and 32 broad-ranging acceptors (sugars, plant hormones, antibiotics, flavonoids, coumarins, phenylpropanoids and benzoic acids). By using the fast-equilibrium assumption, KM, kcat and KIA were determined for representative substrates, and these values were used to determine substrate binding orders. These screening methods applied to the two very different enzymes revealed some unusual substrate specificities, thus highlighting the utility of broad-ranging substrate screening. For UGT72B1, it was shown that the donor specificity is determined largely by the nucleotide moiety. The method is therefore capable of identifying GT enzymes with usefully broad carbohydrate-transfer ability. << Less

Chembiochem 6:346-357(2005) [PubMed] [EuropePMC]
The synthesis of lactose by particulate enzyme preparations from guinea pig and bovine mammary glands.

WATKINS W.M., HASSID W.Z.

J Biol Chem 237:1432-1440(1962) [PubMed] [EuropePMC]
Lactose synthetase.

Hill R.L., Brew K.

Adv Enzymol Relat Areas Mol Biol 43:411-490(1975) [PubMed] [EuropePMC]

RHEA:12404 UDP-alpha-D-galactose + D-glucose = lactose + UDP + H(+)

Enzymes

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Cross-references

Publications

Alpha-lactalbumin and the lactose synthetase reaction.

High-throughput mass-spectrometry monitoring for multisubstrate enzymes: determining the kinetic parameters and catalytic activities of glycosyltransferases.

The synthesis of lactose by particulate enzyme preparations from guinea pig and bovine mammary glands.

Lactose synthetase.