| dihydroorotate oxidase | <enzyme> An enzyme that in the course of pyrimidine biosynthesis, catalyses the oxidation of dihydro-orotic acid to orotic acid utilizing oxygen as the electron acceptor. This enzyme is a flavoprotein which contains both fad and fmn as well as iron-sulfur centres. Chemical name: (S)-Dihydroorotate:oxygen oxidoreductase Registry number: EC 1.3.3.1 (12 Dec 1998) |
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| dihydroorotate-ubiquinone oxidoreductase | <enzyme> From bovine liver mitochondria; uses ubiquinone Registry number: EC 1.3.5- Synonym: dihydroorotate dehydrogenase (ubiquinone), dhoo-dehydrogenase-u (26 Jun 1999) |
| dihydroprogesterone | <chemical> 20 alpha-hydroxypregn-4-en-3-one. A naturally occurring progesterone derivative with progestational activity. Chemical name: Pregn-4-en-3-one, 20-hydroxy-, (20S)- (12 Dec 1998) |
| dihydropteridine reductase | <enzyme> An enzyme that catalyses the reduction of 6,7-dihydropteridine to 5,6,7,8-tetrahydropteridine. Chemical name: NAD(P)H:6,7-dihydropteridine oxidoreductase Registry number: EC 1.6.99.7 (12 Dec 1998) |
| dihydropterin oxidase | <enzyme> From drosophila melanogaster; uses a variety of 2-amino-4-oxo-7,8-dihydropteridine cpds as substrates; during reaction 1 mole of molecular o2 is consumed/mole substrate oxidised producing h2o2 Registry number: EC 1.5.3.- (26 Jun 1999) |
| dihydropteroate synthase | <enzyme> An enzyme that catalyses the formation of dihydropteroate from p-aminobenzoic acid and dihydropteridine-hydroxymethyl-pyrophosphate. Chemical name: 2-Amino-4-hydroxy-6-hydroxymethyl-7,8-dihydropteridine-diphosphate:4-aminobenzoate 2-amino-4-hydroxydihydropteridine-6-methenyltransferase Registry number: EC 2.5.1.15 (12 Dec 1998) |
| dihydropteroic acid | An intermediate in the formation of folic acid; a compound of 6-hydroxymethylpterin and p-aminobenzoic acid, the combining of which is inhibited by sulfonamides. (05 Mar 2000) |
| dihydropyridine | <drug> For example nifedipine and nitrenidine, specific blockers of some types of calcium channel. (18 Nov 1997) |
| dihydropyridines | Pyridine moieties which are partially saturated by the addition of two hydrogen atoms in any position. (12 Dec 1998) |
| dihydropyrimidinase | <enzyme> Catalyses the hydrolytic cleavage of imides that range from linear to heterocyclic and that include hydantoins, dihydropyrimidines and phthalimides; displays stereoselectivity and stereospecificity for some substrates Registry number: EC 3.5.2.2 Synonym: hydantoinase, hydropyrimidine hydrase, dhpase, dihydropyrimidine acid hydrolase, dihydropyrimidine amidohydrolase, imidase, dihydropyrimidine aminohydrolase (26 Jun 1999) |
| dihydropyrimidine dehydrogenase | <enzyme> An enzyme in pyrimidine biosynthesis that reacts 5,6-dihydrouracil with NADP+ to form uracil and NADPH; it also acts on dihydrothymine; a deficiency of this enzyme can result in hyperuracil thyminuria. Synonym: dihydrouracil dehydrogenase. (05 Mar 2000) |
| dihydrostreptomycin | An aminoglycoside antibiotic similar in action to streptomycin but with a higher risk of ototoxicity. (05 Mar 2000) |
| dihydrostreptomycin sulfate | <chemical> A semi-synthetic aminoglycoside antibiotic that is used in the treatment of tuberculosis. Pharmacological action: antibiotics, aminoglycoside, antibiotics, antitubercular. Chemical name: D-Streptamine, O-2-deoxy-2-(methylamino)-alpha-L-glucopyranosyl-(1-2)-O-5-deoxy- 3-C-(hydroxymethyl)-alpha-L-lyxofuranosyl-(1-4)-N,N'-bis(aminoiminomethyl)-, sulfate (2:3) (salt) (12 Dec 1998) |
| dihydrostreptomycin-6-phosphate 3' alpha-kinase | <enzyme> Catalyses the phosphorylation of dihydrostreptomycin 6-phosphate in the 3'-position in the presence of ATP Registry number: EC 2.7.1.88 Synonym: dihydrostreptomycin-6-p 3' alpha-kinase (26 Jun 1999) |
| dihydrotachysterol | <chemical> 9,10-secoergosta-5,7,22-trien-3 beta-ol. Chemical name: 9,10-Secoergosta-5,7,22-trien-3-ol, (3beta,5E,7E,10alpha,22E)- (12 Dec 1998) |