Müller H M, Frosch S
Arch Microbiol. 1975 Jun 22;104(2):159-62. doi: 10.1007/BF00447318.
Carbon-14 was incorporated into oxalate and CO2 from either citrate-1,5-14C, succinate-1,4-14C, or fumarate-1,4-14C by cultures of Aspergillus niger pregrown on a medium which contained glucose as the sole carbon source and which did not allow citrate accumulation. In cell-free extracts of mycelium forming oxalate and CO2 from added citrate the following enzymes of the tricarboxylic acid (TCA) cycle were identified: citrate synthase CE 4.1.3.7), aconitate hydratase (EC4.2.1.3), NAD and NADP-dependent isocitrate dehydrogenase (EC 1.1.1.41, 1.1.1.42), (alpha-oxoglutarate dehydrogenase (EC 1.2.4.2), succinate dehydrogenase (EC 1.3.99.1), fumarate hydratase (EC 4.2.1.2), and malate dehydrogenase (EC 1.1.1.37). The in vitro activity of aconitate hydratase and of NADP-dependent isocitrate dehydrogenase was shown to be almost identical to the rate of in vivo degradation of citrate or to exceed this rate. The degradation of citrate to oxalate was inhibited completely by 9 mM fluoroacetate. It is concluded that the TCA cycle is involved in the formation of oxalate from citrate.
将黑曲霉培养物接种在以葡萄糖作为唯一碳源且不允许柠檬酸盐积累的培养基上预培养，这些培养物可将碳 - 14 从柠檬酸 - 1,5 - 14C、琥珀酸 - 1,4 - 14C 或富马酸 - 1,4 - 14C 掺入草酸盐和二氧化碳中。在由添加的柠檬酸盐形成草酸盐和二氧化碳的菌丝体的无细胞提取物中，鉴定出了三羧酸（TCA）循环的以下几种酶：柠檬酸合酶（CE 4.1.3.7）、乌头酸水合酶（EC4.2.1.3）、NAD 和 NADP 依赖性异柠檬酸脱氢酶（EC 1.1.1.41、1.1.1.42）、α - 酮戊二酸脱氢酶（EC 1.2.4.2）、琥珀酸脱氢酶（EC 1.3.99.1）、富马酸水合酶（EC 4.2.1.2）和苹果酸脱氢酶（EC 1.1.1.37）。结果表明，乌头酸水合酶和 NADP 依赖性异柠檬酸脱氢酶的体外活性几乎与柠檬酸盐的体内降解速率相同，或超过该速率。9 mM 的氟乙酸可完全抑制柠檬酸盐向草酸盐的降解。得出的结论是，三羧酸循环参与了由柠檬酸盐形成草酸盐的过程。
