| steroid | A group name for lipids that contain a hydrogenated cyclopentanoperhydrophenanthrene ring system. Some of the substances included in this group are progesterone, adrenocortical hormones, the gonadal hormones, cardiac aglycones, bile acids, sterols (such as cholesterol), toad poisons, saponins and some of the carcinogenic hydrocarbons. (18 Nov 1997) |
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| steroid 11-alpha-hydroxylase | <enzyme> Converts 11-deoxycortisol to 11-alpha cortisol (the 11-alpha isomer of hydrocortisone) Registry number: EC 1.14.99.- (26 Jun 1999) |
| steroid 11 beta-monooxygenase | <enzyme> A steroid hydroxylase system found in adrenal tissues. It catalyses the 11-hydroxylation of steroids in the presence of molecular oxygen and consists of an NADPH-specific flavoprotein, a non-haem iron protein, and cytochrome p-450. Its deficiency is a cause of congenital adrenal hyperplasia (adrenal hyperplasia, congenital). Chemical name: Steroid, reduced-adrenal-ferredoxin:oxygen oxidoreductase (11 beta-hydroxylating) Registry number: EC 1.14.15.4 (12 Dec 1998) |
| steroid 12-monooxygenase | <enzyme> A steroid hydroxylase found in liver microsomes. It catalyses the 12-hydroxylation of steroids in the presence of NADPH, cytochrome p-450, and molecular oxygen. It is an important enzyme in the synthesis of cholic acid from cholesterol in the liver. Chemical name: Steroid, hydrogen-donor:oxygen oxidoreductase (12-alpha-hydroxylating) Registry number: EC 1.14.99.- (12 Dec 1998) |
| steroid 14-alpha-hydroxylase | <enzyme> From induced vegetative cell cultures of mucor piriformis; hydroxylates progesterone to 14-alpha-hydroxyprogesterone in the presence of NADPH and oxygen Registry number: EC 1.14.13.- Synonym: progesterone 14-alpha-hydroxylase (26 Jun 1999) |
| steroid 15-beta-hydroxylase | <enzyme> Contains p-450 and ferredoxin; from bacillus megaterium Registry number: EC 1.14.99.- Synonym: cytochrome p-450 15 beta-hydroxylase, p-450 (15-beta), steroid-15 beta-monooxygenase, cytochrome p-450meg, cytochrome p4502c12, cyp2c12 protein (26 Jun 1999) |
| steroid 17 alpha-monooxygenase | <enzyme> A steroid hydroxylase system found in the microsomal membrane of the steroid-hormone producing tissues. It catalyses the 17-hydroxylation of steroids, such as progesterone or pregnenolone in the presence of NADPH and molecular oxygen. This is an important step in the biosynthesis of steroid hormones. Chemical name: Steroid, hydrogen-donor:oxygen oxidoreductase (17 alpha-hydroxylating) Registry number: EC 1.14.99.9 (12 Dec 1998) |
| steroid 19-hydroxylase | <enzyme> Enzyme from adrenal mitochondria; forms 19-hydroxy-11-deoxycorticosterone Registry number: EC 1.14.13.- Synonym: 19-hydroxysteroid hydroxylase, deoxycorticosterone 11-19-hydroxylase (26 Jun 1999) |
| steroid 21-monooxygenase | <enzyme> A steroid hydroxylase system found in adrenal cortex microsomes. It catalyses the 21-hydroxylation of corticosteroids and shows a requirement for NADPH and molecular oxygen. Its deficiency is a cause of adrenogenital syndrome. Chemical name: Steroid,hydrogen-donor:oxygen oxidoreductase (21-hydroxylating) Registry number: EC 1.14.99.10 (12 Dec 1998) |
| steroid (23R)-hydroxylase | <enzyme> Increased (23r)-hydroxylase activity in patients with cerebrotendinous xanthomatosis, an inborn error of metabolism in bile acid synthesis resulting in (23r)-hydroxylation of bile acids Registry number: EC 1.14.99.- Synonym: bile acid (23r)-hydroxylase, bile alcohol (23r)-hydroxylase (26 Jun 1999) |
| steroid 25-hydroxylase | <enzyme> Involved in cholesterol degradation to cholic acid Registry number: EC 1.14.99.- (26 Jun 1999) |
| steroid 5a-reductase | <enzyme> An enzyme that uses NADPH to reduce certain steroids (e.g., the conversion of testosterone to dihydrotestosterone a deficiency of this enzyme is associated with a form of male pseudohermaphroditism in which genetic males have male genitals as well as female external genitalia. (05 Mar 2000) |
| steroid 7 alpha-hydroxylase | <enzyme> Testosterone and androstenedione incubated with microsomes from rat testes produced 7alpha-hydroxytestosterone and 7alpha-hydroxyandrostenedione Registry number: EC 1.14.99.- Synonym: testicular 7 alpha-hydroxylase, 7 alpha-hydroxylase, microsomal 7alpha-hydroxylase, andiostenedione 7 alpha-hydroxylase, sterol 7 alpha-hydroxylase, cytochrome p-450iia1, cytochrome p450iia1 (26 Jun 1999) |
| steroid 9 alpha monooxygenase | <enzyme> Consists of an electron transport chain of NADH-dependent flavoprotein reductase and 2 iron-sulfur proteins; from nocardia Registry number: EC 1.14.99.- Synonym: steroid 9 alpha-hydroxylase (26 Jun 1999) |
| steroid acne | Folliculitis similar to acne vulgaris, but resulting from topical or oral administration of steroids; comedones are rare. (05 Mar 2000) |