Abstract
Four types of 17beta-hydroxysteroid dehydrogenases have been identified so far. The porcine peroxisomal 17beta-hydroxysteroid dehydrogenase type IV catalyzes the oxidation of estradiol with high preference over the reduction of estrone. A 2.9-kilobase mRNA codes for an 80-kDa (737 amino acids) protein featuring domains which are not present in the other 17beta-hydroxysteroid dehydrogenases. The 80-kDa protein is N terminally cleaved to a 32-kDa fragment with 17beta-hydroxysteroid dehydrogenase activity. Here we show for the first time that both the 80-kDa and the N-terminal 32 kDa (amino acids 1-323) peptides are able to perform the dehydrogenase reaction not only with steroids at the C17 position but also with 3-hydroxyacyl-CoA. The central part of the 80-kDa protein (amino acids 324-596) catalyzes the 2-enoyl-acyl-CoA hydratase reaction with high efficiency. The C-terminal part of the 80-kDa protein (amino acids 597-737) is similar to sterol carrier protein 2 and facilitates the transfer of 7-dehydrocholesterol and phosphatidylcholine between membranes in vitro. The unique multidomain structure of the 80-kDa protein allows for the catalysis of several reactions so far thought to be performed by complexes of different enzymes.
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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17-Hydroxysteroid Dehydrogenases / biosynthesis
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17-Hydroxysteroid Dehydrogenases / metabolism*
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Acyl-CoA Dehydrogenase
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Animals
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Base Sequence
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Carrier Proteins / biosynthesis
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Carrier Proteins / metabolism*
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Cattle
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Cell Line
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Cloning, Molecular
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DNA Primers
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Enoyl-CoA Hydratase / biosynthesis
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Enoyl-CoA Hydratase / metabolism*
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Escherichia coli
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Fatty Acid Desaturases / biosynthesis
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Fatty Acid Desaturases / metabolism*
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Fatty Acid-Binding Protein 7
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Fatty Acid-Binding Proteins
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Fatty Acids / metabolism
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Gene Expression
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Humans
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Kidney
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Kinetics
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Molecular Sequence Data
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Molecular Weight
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Myelin P2 Protein / biosynthesis
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Myelin P2 Protein / metabolism*
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Neoplasm Proteins*
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Phosphatidylcholines / metabolism
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Polymerase Chain Reaction
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RNA, Messenger / metabolism
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / metabolism
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Swine
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Transfection
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Tumor Suppressor Proteins*
Substances
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Carrier Proteins
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DNA Primers
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FABP7 protein, human
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Fatty Acid-Binding Protein 7
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Fatty Acid-Binding Proteins
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Fatty Acids
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Myelin P2 Protein
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Neoplasm Proteins
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Phosphatidylcholines
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RNA, Messenger
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Recombinant Proteins
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Tumor Suppressor Proteins
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17-Hydroxysteroid Dehydrogenases
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Fatty Acid Desaturases
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Acyl-CoA Dehydrogenase
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Enoyl-CoA Hydratase