Abstract
Human liver contains two dihydrodiol dehydrogenases, DD2 and DD4, associated with 3 alpha-hydroxysteroid dehydrogenase activity. We have raised polyclonal antibodies that cross-reacted with the two enzymes and isolated two 1.2 kb cDNA clones (C9 and C11) for the two enzymes from a human liver cDNA library using the antibodies. The clones of C9 and C11 contained coding sequences corresponding to 306 and 321 amino acid residues respectively, but lacked 5'-coding regions around the initiation codon. Sequence analyses of several peptides obtained by enzymic and chemical cleavages of the two purified enzymes verified that the C9 and C11 clones encoded DD2 and DD4 respectively, and further indicated that the sequence of DD2 had at least additional 16 residues upward from the N-terminal sequence deduced from the cDNA. There was 82% amino acid sequence identity between the two enzymes, indicating that the enzymes are genetic isoenzymes. A computer-based comparison of the cDNAs of the isoenzymes with the DNA sequence database revealed that the nucleotide and amino acid sequences of DD2 and DD4 are virtually identical with those of human bile-acid binder and human chlordecone reductase cDNAs respectively.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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3-Hydroxysteroid Dehydrogenases / biosynthesis
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3-Hydroxysteroid Dehydrogenases / genetics*
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3-alpha-Hydroxysteroid Dehydrogenase (B-Specific)
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Alcohol Oxidoreductases / biosynthesis
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Alcohol Oxidoreductases / genetics*
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Amino Acid Sequence
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Base Sequence
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Bile Acids and Salts / metabolism
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Carrier Proteins / genetics*
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Cloning, Molecular
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DNA / genetics
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DNA / metabolism
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DNA, Complementary / metabolism
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Gene Library
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Humans
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Hydroxysteroid Dehydrogenases*
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Isoenzymes / biosynthesis
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Isoenzymes / genetics*
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Liver / enzymology*
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Membrane Glycoproteins*
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Molecular Sequence Data
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NAD (+) and NADP (+) Dependent Alcohol Oxidoreductases
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Oxidoreductases Acting on CH-CH Group Donors*
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Oxidoreductases*
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Peptide Fragments / chemistry
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Peptide Fragments / isolation & purification
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Restriction Mapping
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Sequence Homology, Amino Acid
Substances
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Bile Acids and Salts
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Carrier Proteins
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DNA, Complementary
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Isoenzymes
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Membrane Glycoproteins
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Peptide Fragments
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bile acid binding proteins
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DNA
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Oxidoreductases
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3-Hydroxysteroid Dehydrogenases
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Alcohol Oxidoreductases
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Hydroxysteroid Dehydrogenases
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dihydrodiol dehydrogenases
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NAD (+) and NADP (+) Dependent Alcohol Oxidoreductases
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chlordecone reductase
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AKR1C2 protein, human
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3-alpha-Hydroxysteroid Dehydrogenase (B-Specific)
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Oxidoreductases Acting on CH-CH Group Donors
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cis-1,2-dihydro-1,2-dihydroxynaphthalene dehydrogenase
Associated data
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GENBANK/D26124
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GENBANK/D26125