Cytochrome P450c17 from porcine and bovine adrenal catalyses the formation of 5,16-androstadien-3β-ol from pregnenolone in the presence of cytochrome b5
| Autor: | E. J. Squires, W.J. Meadus, J.I. Mason |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Male
Cytochrome Swine Endocrinology Diabetes and Metabolism Clinical Biochemistry 25-Hydroxyvitamin D3 1-alpha-hydroxylase Biology Biochemistry Endocrinology Microsomes Adrenal Glands Testis Cytochrome b5 Animals Cytochrome c oxidase RNA Messenger Lyase activity Molecular Biology Androstenols Cytochrome b Cytochrome c Steroid 17-alpha-Hydroxylase Cytochrome P450 reductase Cell Biology Molecular biology Cytochromes b5 Pregnenolone biology.protein Molecular Medicine Cattle Female |
| Zdroj: | The Journal of Steroid Biochemistry and Molecular Biology. 46:565-572 |
| ISSN: | 0960-0760 |
| Popis: | The synthesis of 5,16-androstadien-3β-ol from pregnenolone occurs via a cytochrome P 450-dependent reaction (andien-β synthase) that is analogous to the C17-hydroxylase/lyase reaction. It is not known whether the andien-β synthase activity in adult porcine testis involves cytochrome P 450c17 or is unique to porcine testis. Andien-β synthase activity in testis microsomes was inhibited by high pH and concentration of salt, while C17-hydroxylase/lyase activity was stimulated under these conditions. Cytochrome P450c17 purified from adult porcine testis and adrenal glands and bovine adrenal glands had only C17-hydroxylase/lyase activity in the absence of cytochrome b 5 . However, when cytochrome b 5 isolated from porcine testis was added, andien-β synthase activity was detected in all three preparations of cytochrome P 450c17, with the highest activity found in the porcine preparations. The andien-β synthase activity was further increased from 2.5 to 6 times when NADH cytochrome b 5 reductase was added along with cytochrome b 5 . Levels of mRNA for cytochrome b 5 relative to cytochrome P 450c17 mRNA were five times higher in porcine testis than in porcine adrenal. It appears that the andien-β synthase activity is catalysed by cytochrome P 450c17, which is not unique to the porcine testis and is dependent upon adequate levels of cytochrome b 5 . |
| Databáze: | OpenAIRE |
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