| quinone | Aromatic dicarbonyl compound derived from a dihydroxy aromatic compound. Ubiquinone (coenzyme Q) is a dimethoxy dicarbonyl derivative of benzene involved in electron transport. Other quinones may act as tanning agents. (18 Nov 1997) |
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| quinone methide isomerase | <enzyme> From insect cuticle; converts 4-alkyl catechols to quinone methides Registry number: EC 5.3.2.- Synonym: o-quinone-quinone methide isomerase, 4-alkyl-o-quinone-2-hydroxy-4-quinone methide isomerase (26 Jun 1999) |
| quinone methide tautomerase | <enzyme> Enzyme from insect cuticle converts n-acetyldopamine quionone methide to 1,2-dehydro-n-acetyldopamine Registry number: EC 5.3.2.- Synonym: nada quione methide tautomerase (26 Jun 1999) |
| quinone reductases | <enzyme> NAD(p)h:(quinone acceptor) oxidoreductases. A family that includes three enzymes which are distinguished by their sensitivity to various inhibitors. (NAD(p)h dehydrogenase (quinone)) is a flavoprotein which reduces various quinones in the presence of NADH or NADPH and is inhibited by dicoumarol. (NADH dehydrogenase (quinone)) requires NADH, is inhibited by AMP and 2,4-dinitrophenol but not by dicoumarol or folic acid derivatives. (NADPH dehydrogenase (quinone)) requires NADPH and is inhibited by dicoumarol and folic acid derivatives but not by 2,4-dinitrophenol. Registry number: EC 1.6.99. (12 Dec 1998) |
| lead sulfide | The native form in which lead is chiefly found. Synonym: galena. (05 Mar 2000) |
| acetoacetyl-CoA reductase | An oxidoreductase catalyzing interconversion of a 3-oxoacyl-CoA and NADPH, and the corresponding d-3-hydroxyacyl-CoA, and NADP+. A step in fatty acid synthesis. (05 Mar 2000) |
| acetohexamide reductase | <enzyme> Catalyses the conversion of acetohexamide to (-)-hydroxyhexamide Registry number: EC 1.1.1.- (26 Jun 1999) |
| acryloyl-CoA reductase | <enzyme> Clostridium kluyveri enzyme; contains fmn, ferredoxin, and flavodoxin; can act as electron donors Registry number: EC 1.3.99.- Synonym: acryloyo-coenzyme a reductase (26 Jun 1999) |
| aflatoxin B1 aldehyde reductase | <enzyme> Catalyses the conversion of the dialdehydic form of aflatoxin b1-dihydrodiol to the dialcohol form Registry number: EC 1.1.1.- Synonym: aflatoxin b1-aldehyde reductase, afb1-ar (26 Jun 1999) |
| aflatoxin B1 reductase | <enzyme> Reduces the cyclopentenone ring of aflatoxin b1 to aflatoxicol; requires NADPH as cofactor Registry number: EC 1.1.1.- (26 Jun 1999) |
| aflatoxin G2a reductase | <enzyme> Has broad substrate specificity in cell-free extracts from aspergillus parasiticus; versicolorin a hemiacetal is reduced to versicolorin c; 17-hydroxy-16,17-dihydrosterigmatocystin is reduced to a 14,17-hydrated derivative; aflatoxin g2a is converted to a 13,16-hydrated derivative of afg2 Registry number: EC 1.1.1.- (26 Jun 1999) |
| aldehyde reductase | <enzyme> An enzyme that catalyses reversibly the oxidation of an aldose to an alditol. It possesses broad specificity for many aldoses. Chemical name: Alditol:NAD(P)+ 1-oxidoreductase Registry number: EC 1.1.1.21 (12 Dec 1998) |
| aldose reductase | A polyol dehydrogenase (NADP+);an oxidoreductase that reversibly converts aldoses to alditols (e.g., glucose to sorbitol) with NADPH as hydrogen donor. An important step in the metabolism of sorbitol and in the formation of diabetic cataracts. See: d-sorbitol-6-phosphate dehydrogenase. (05 Mar 2000) |
| aldose reductase inhibitor | <pharmacology> A class of drugs being studied as a way to prevent eye and nerve damage in people with diabetes. Aldose reductase is an enzyme that is normally present in the eye and in many other parts of the body. It helps change glucose (sugar) into a sugar alcohol called sorbitol. Too much sorbitol trapped in eye and nerve cells can damage these cells, leading to retinopathy and neuropathy. Drugs that prevent or slow (inhibit) the action of aldose reductase are being studied as a way to prevent or delay these complications of diabetes. (09 Oct 1997) |
| alkyl hydroperoxide reductase | <enzyme> Reduces an alkyl hydroperoxide to the corresponding alcohol in the presence of NADPH; ahpc gene product from salmonella typhimurium Registry number: EC 1.- Synonym: ahpc gene product, alkylhydroperoxide reductase, ahpf gene product (26 Jun 1999) |