| 21-hydroxyprogesterone | 11-Deoxycorticosterone; 21-hydroxypregn-4-ene-3,20-dione;an adrenocortical steroid, principally a biosynthetic precursor of corticosterone and possibly aldosterone, that rarely appears in adrenocortical secretions; a potent mineralocorticoid with no appreciable glucocorticoid activity. Synonym: 21-hydroxyprogesterone, cortexone, deoxycortone, desoxycortone. Deoxycorticosterone acetate, desoxycorticosterone acetate;acetate salt used for intramuscular injection for replacement therapy of the adrenocortical steroid. Deoxycorticosterone pivalate, desoxycorticosterone pivalate;pivalate salt of the steroid. (05 Mar 2000) |
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| 22,6-dichloro-4-hydroquinone chlorohydrolase | <enzyme> Catalyses conversion of 2,6-dichloro-4-hydroquinone to 6-chloro-1,2,4-trihydroxybenzene; isolated from flavobacterium Registry number: EC 3.8.1.- Synonym: 2,6-dich chlorohydrolase, 2,6-dichloro-p-hydroquinone chlorohydrolase (26 Jun 1999) |
| 24,25-dihydrolanosterol 14 alpha-oxidase | <enzyme> Oxidatively removes the 14 alpha-methyl group of sterols as formic acid; cytochrome p-450 dependent Registry number: EC 1.14.13.- Synonym: 14 alpha-methyl sterol oxidase (26 Jun 1999) |
| 24,25-dihydroxyvitamin d 3 | <chemical> 9,10-secocholesta-5,7,10(19)-triene 3,24,25-triol. A physiologically active metabolite of vitamin d. The compound is involved in the regulation of calcium metabolism, alkaline phosphatase activity, and enhances the calcaemic effect of calcitriol. Chemical name: 9,10-Secocholesta-5,7,10(19)-triene-3,24,25-triol, (3beta,5Z,7E)- (12 Dec 1998) |
| 24-dehydrocholesterol | <chemical> Chemical name: Cholesta-5,24-dien-3-ol, (3beta)- (12 Dec 1998) |
| 24-hour cardiac monitor | <apparatus> A recording device, worn by the patient for the purpose of monitoring the hearts rhythm and rate, over a period of 24 hours. (27 Sep 1997) |
| 24-methylene cycloartanol C4-monodemethylase | <enzyme> Catalyses the c4 demethylation of 24-methylene cycloartanol to cycloeucalenol; the demethylation involves a 4-methyl-4-hydroxymethyl derivative to a 4-methyl-4-carboxylic acid to a 3-keto-4-methyl cpd to the final cpd; requires NADPH and molecular oxygen; strongly inhibited by cyanide Registry number: EC 1.13.99.- Synonym: 24-mcmdase, 4,4-dimethylsterol 4-demethylase (26 Jun 1999) |
| 25-hydroxycholecalciferol | 25-hydroxycholecalciferol (a 3,25-diol);the first step in the biological conversion of vitamin D3 to the more active form, calcitriol; it is more potent than vitamin D3. Synonym: 25-hydroxycholecalciferol, calcifediol. Calcidiol 1a-hydroxylase, 25-hydroxycholecalciferol 1a-hydroxylase, the monooxygenase that forms calcitriol from calcidiol using O2 and NADPH; a deficiency in this enzyme can result in features of a vitamin D deficiency. (05 Mar 2000) |
| 25-hydroxycholecalciferol 1-hydroxylase | <enzyme> An enzyme that catalyses the formation of 1,25-dihydroxycholecalciferol from 25-hydroxycholecalciferol. The reaction requires oxygen, magnesium, and NAD(p)h. Chemical name: Calcidiol,NADPH:oxygen oxidoreductase (1-hydroxylating) Registry number: EC 1.14.13.13 (12 Dec 1998) |
| 25-hydroxycholecalciferol-24-hydroxylase | <enzyme> Cytochrome p-450 monooxygenase system Registry number: EC 1.14.99.- Synonym: 25-hydroxyvitamin d(3)-24-hydroxylase, 25-hydroxyvitamin d(3)-24r-hydroxylase, 25-hc-24-hydroxylase, cytochrome p450cc24, 24-hydroxylase cytochrome p-450, cytochrome p450(24), vitamin d 24-hydroxylase, cyp24 (26 Jun 1999) |
| 25-hydroxycholesterol 7alpha-hydroxylase | <enzyme> Catalyses 7alpha hydroxylation of 25-hydroxycholesterol in liver microsomes; from rat, pig and human; different from cholesterol 7alpha hydroxylase Registry number: EC 1.14.99.- Synonym: 25-hc 7alpha-hydroxylase (26 Jun 1999) |
| 25-hydroxyergocalciferol | A biologically active and major circulatory metabolite of vitamin D2. Synonym: ercalcidiol. (05 Mar 2000) |
| 25-hydroxyvitamin d2 | <chemical> 9,10-secoergosta-5,7,10(19),22-tetraene-3,25-diol. Biologically active metabolite of vitamin d2 which is more active in curing rickets than its parent. The compound is believed to attach to the same receptor as vitamin d2 and 25-hydroxyvitamin d3. Chemical name: 9,10-Secoergosta-5,7,10(19),22-tetraene-3,25-diol, (3beta,5Z,7E,22E)- (12 Dec 1998) |