Intrinsic sterol- and phosphatidylcholine transfer activities of 17β-hydroxysteroid dehydrogenase type IV

• Published in: Journal of steroid biochemistry and molecular biology 1995-12, Vol.55 (5), p.549-553
• Main Authors: Seedorf, U., Engel, T., Assmann, G., Leenders, F., Adamski, J.
• Format: Article
• Language: English
• Subjects: 17-Hydroxysteroid Dehydrogenases - metabolism; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Binding and carrier proteins; Biological and medical sciences; Carrier Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Humans; Isoenzymes - metabolism; Mice; Molecular Sequence Data; Phosphatidylcholines - metabolism; Phylogeny; Plant Proteins; Proteins; Rats; Recombinant Proteins; Sequence Alignment; Sequence Homology, Amino Acid; Sterols - metabolism; Substrate Specificity; Swine
• ISSN: 0960-0760; 1879-1220
• DOI: 10.1016/0960-0760(95)00205-7

Previous studies have shown that the 80 kDa 17β-hydroxysteroid dehydrogenase (17β-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 17β-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 17β-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 17β-HSD represents a potentially multifunctional protein with intrinsic in vitro sterol and phospholipid transfer activity in addition to its enzymatic activity.