Jamaluddin M, Rao P V, Vaidyanathan C S
J Bacteriol. 1970 Mar;101(3):786-93. doi: 10.1128/jb.101.3.786-793.1970.
Cell-free extracts of Aspergillus niger UBC 814 grown in the presence of dl-mandelate oxidized both d(-)- and l(+)-mandelate via benzoylformate and benzaldehyde to benzoate. dl-p-Hydroxymandelate was oxidized, presumably through a parallel pathway, to p-hydroxybenzoate. A particulate d(-)-mandelate dehydrogenase and a supernatant fraction l(+)-mandelate dehydrogenase converted their respective substrates to benzoylformate. Both flavine adenine dinucleotide and flavine mononucleotide showed a stimulatory effect on the activity of the l(+)-mandelate dehydrogenase. Benzoylformate was decarboxylated to benzaldehyde by an enzyme requiring thiamine pyrophosphate for maximal activity. Two benzaldehyde dehydrogenases dependent on nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), respectively, for their activity dehydrogenated benzaldehyde to benzoate. In the presence of reduced NADP (NADPH), benzoate was oxidized via p-hydroxybenzoate and protocatechuate. Reduced NAD could not replace NADPH. Sensitive methods of assay for d(-)-mandelate dehydrogenase and benzoylformate decarboxylase are described. The fungal pathway is compared with these systems in bacteria.
在dl-扁桃酸存在下生长的黑曲霉UBC 814的无细胞提取物通过苯甲酰甲酸和苯甲醛将d(-)-和l(+)-扁桃酸氧化为苯甲酸。dl-p-羟基扁桃酸大概通过一条平行途径被氧化为对羟基苯甲酸。一种颗粒状的d(-)-扁桃酸脱氢酶和一种上清液组分中的l(+)-扁桃酸脱氢酶将各自的底物转化为苯甲酰甲酸。黄素腺嘌呤二核苷酸和黄素单核苷酸对l(+)-扁桃酸脱氢酶的活性均有刺激作用。苯甲酰甲酸通过一种需要焦磷酸硫胺素以达到最大活性的酶脱羧生成苯甲醛。两种分别依赖烟酰胺腺嘌呤二核苷酸（NAD）和烟酰胺腺嘌呤二核苷酸磷酸（NADP）发挥活性的苯甲醛脱氢酶将苯甲醛脱氢生成苯甲酸。在还原型NADP（NADPH）存在的情况下，苯甲酸通过对羟基苯甲酸和原儿茶酸被氧化。还原型NAD不能替代NADPH。文中描述了d(-)-扁桃酸脱氢酶和苯甲酰甲酸脱羧酶的灵敏测定方法。将真菌的代谢途径与细菌中的这些系统进行了比较。
