产品内容
本酶催化的反应为24-Methylidenecycloartanol + 6 Ferrocytochrome B5 + 3 O2 + 6 H+ = 3beta-Hydroxy-4beta,14alpha-Dimethyl-9beta,19-Cyclo-5alpha-Ergost-24(241)-En-4alpha-Carboxylate + 6 Ferricytochrome B5 + 4 H2O (Overall Reaction);;(1a) 24-Methylidenecycloartanol + 2 Ferrocytochrome B5 + O2 + 2 H+ = 4alpha-(Hydroxymethyl)-4beta,14alpha-Dimethyl-9beta,19-Cyclo-5alpha-Ergost-24(241)-En-3beta-Ol + 2 Ferricytochrome B5 + H2O;;(1b) 4alpha-(Hydroxymethyl)-4beta,14alpha-Dimethyl-9beta,19-Cyclo-5alpha-Ergost-24(241)-En-3beta-Ol + 2 Ferrocytochrome B5 + O2 + 2 H+ = 4alpha-Formyl-4beta,14alpha-Dimethyl-9beta,19-Cyclo-5alpha-Ergost-24(241)-En-3beta-Ol + 2 Ferricytochrome B5 + 2 H2O;;(1c) 4alpha-Formyl-4beta,14alpha-Dimethyl-9beta,19-Cyclo-5alpha-Ergost-24(241)-En-3beta-Ol + 2 Ferrocytochrome B5 + O2 + 2 H+ = 3beta-Hydroxy-4beta,14alpha-Dimethyl-9beta,19-Cyclo-5alpha-Ergost-24(241)-En-4alpha-Carboxylate + 2 Ferricytochrome B5 + H2O,系统名称为24-Methylidenecycloartanol,ferrocytochrome-B5:oxygen Oxidoreductase (C-4alpha-Methyl-Hydroxylating),这种植物酶催化甾醇生物合成中的一步。它作用于 4,4-二甲基化中间体 24-亚甲基环阿屯醇的 4α-甲基,催化三次连续氧化,将其转变为羧基。羧酸根随后被 EC 1.1.1.418(植物 3β-羟基甾体-4α-羧酸 3-脱氢酶(脱羧型))去除,该酶还催化剩余的 4β-甲基差向异构化为 4α 位。与真菌/动物酶 EC 1.14.18.9(4α-甲基甾醇单加氧酶)不同,该酶不能去除 C-4 单甲基化底物上的甲基。该活性在植物中由第二种酶 EC 1.14.18.11(植物 4α-单甲基甾醇单加氧酶)执行。