Intrinsic sterol- and phosphatidylcholine transfer activities of 17 beta-hydroxysteroid dehydrogenase type IV.
Previous studies have shown that the 80 kDa 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) type IV comprises distinct domains, including an N-terminal region related to the short chain alcohol dehydrogenase multigene family and a C-terminal part related to the lipid transfer protein sterol carrier protein 2 (SCP2). In this study, we have investigated whether the SCP2-related part of the 80 kDa protein leads to an intrinsic sterol and phospholipid transfer activity, as shown earlier for the 60 kDa SCP2-related peroxisomal 3-ketoacyl CoA thiolase with intrinsic sterol and phospholipid transfer activity called sterol carrier protein x (SCPx). Our results indicate that a fraction rich in the 80 kDa form of 17 beta-HSD type IV exhibits high transfer activities for 7-dehydrocholesterol and phosphatidylcholine. In addition, a purified recombinant peptide derived from the SCP2-related domain of the 17 beta-HSD type IV has about 30% of the transfer activities for 7-dehydrocholesterol and phosphatidylcholine seen with purified recombinant human SCP2. We conclude that the 80 kDa type IV 17 beta-HSD represents a potentially multifunctional protein with intrinsic in vitro sterol and phospholipid transfer activity in addition to its enzymatic activity.
Institut für Arterioskeleroseforschung, Zentrallaboratorium, Westfälische Wilhelms-Universität, Münster, Germany.
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Seedorf
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Engel
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Assmann
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Leenders
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Adamski
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010713:Phosphatidylcholines / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins; D051381:Rats; D011994:Recombinant Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013261:Sterols / Q000378:metabolism*; D013379:Substrate Specificity; D013552:Swine
D002352:Carrier Proteins; D007527:Isoenzymes; D010713:Phosphatidylcholines; D010940:Plant Proteins; D011994:Recombinant Proteins; D013261:Sterols; C072087:sterol carrier proteins; D015067:17-Hydroxysteroid Dehydrogenases