| dihdroxyindole-carboxylic acid oxidase | <enzyme> Converts 5,6-dihydroxyindole-2-carboxylic acid to melanochrome in premelanosomes; no further information on mechanism 6/95 Registry number: EC 1.- Synonym: dhica oxidase, dhi2c oxidase (26 Jun 1999) |
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| dihematoporphyrin ether | <chemical> The purified component of haematoporphyrin derivative, it consists of a mixture of oligomeric porphyrins. It is used in photodynamic therapy (haematoporphyrin photoradiation) to treat malignant lesions with visible light and experimentally as an antiviral agent. It is the first drug to be approved in the use of photodynamic therapy in the united states. Pharmacological action: antineoplastic agent, antiviral agents, dermatologic agents. Chemical name: 21H,23H-Porphine-2,18-dipropanoic acid, 7-(1-(1-(8,12-bis(2-carboxyethyl)-17-(1-hydroxyethyl)-3,7,13,18-tetramethyl-21H,23H-porphin-2-yl)ethoxy)ethyl)-12-(1-hydroxyethyl)-3,8,13,17-tetramethyl- (12 Dec 1998) |
| diheterozygote | An individual heterozygous at two loci of interest, especially in genetic linkage analysis. (05 Mar 2000) |
| dihexagonal | Consisting of two hexagonal parts united; thus, a dihexagonal pyramid is composed of two hexagonal pyramids placed base to base. Having twelve similar faces; as, a dihexagonal prism. Origin: Pref. Di- + hexagonal. Source: Websters Dictionary (01 Mar 1998) |
| dihybrid | The offspring of parents differing in two characters. Origin: G. Di-, two, + L. Hybrida, offspring of a tame sow and a wild boar (05 Mar 2000) |
| dihydralazine | <chemical> 1,4-dihydrazinophthalazine. An antihypertensive agent with actions and uses similiar to those of hydralazine. Pharmacological action: antihypertensive agents. Chemical name: 1,4-Phthalazinedione, 2,3-dihydro-, dihydrazone (12 Dec 1998) |
| dihydrate | A compound with two molecules of water of crystallization. (05 Mar 2000) |
| dihydrazone | The compound formed by certain sugars (e.g., glucose, galactose, fructose) with excess hydrazines, possessing two hydrazones on carbons 1 and 2 instead of only one at C-1, as in the ordinary hydrazone; osazone's formed with phenylhydrazine (phenylosazones) are used to characterise and identify certain sugars. Synonym: dihydrazone. (05 Mar 2000) |
| dihydric alcohol | Alcohol containing two OH groups in its molecule; e.g., ethylene glycol. (05 Mar 2000) |
| dihydro- | <prefix> Prefix indicating the addition of two hydrogen atoms. Origin: G. Di, two + hydr, water (05 Mar 2000) |
| dihydro-beta-erythroidine | <chemical> Dihydro analog of beta-erythroidine, which is isolated from the seeds and other plant parts of erythrina sp. Leguminosae. It is an alkaloid with curarimimetic properties. Chemical name: 16(15H)-Oxaerythrinan-15-one, 1,6-didehydro-14,17-dihydro-3-methoxy-, (3beta)- (12 Dec 1998) |
| dihydro-orotate | <biochemistry> An intermediate in the biosynthesis of pyrimidines. Chemical name: L-5,6-dihydroorotate (21 Jun 2000) |
| dihydroalprenolol | <chemical> Hydrogenated alprenolol derivative where the extra hydrogens are often tritiated. This radiolabelled form of alprenolol, a beta-adrenergic blocker, is used to label the beta-adrenergic receptor for isolation and study. Pharmacological action: adrenergic beta-antagonists, anti-arrhythmia agents, antihypertensive agents, sympatholytics. Chemical name: 2-Propanol, 1-((1-methylethyl)amino)-3-(2-propylphenoxy)- (12 Dec 1998) |
| dihydroanisoin dehydrogenase | <enzyme> Catalyses the NADH-dependent reduction of the carbonyl group of benzoin and anisoin; oxidoreductases from pseudomonas fluorescens biovar i Registry number: EC 1.1.1.- (26 Jun 1999) |
| dihydroascorbic acid | The immediate precursor of ascorbic acid in those animals capable of ascorbic acid biosynthesis. Synonym: dihydroascorbic acid, l-gulono-gamma-lactone. L-gulonolactone oxidase, the enzyme catalyzing the conversion of l-gulonolactone and O2 to H2O2 and l-xylo-hexulonolactone, a precursor of ascorbic acid; absent in primates. (05 Mar 2000) |