Müller H M
Arch Microbiol. 1975 Apr 7;103(2):185-9. doi: 10.1007/BF00436348.
Carbon-14 was incorporated from citrate-1,5-14C, glyoxylate-14C(U), or glyoxylate-1-14C into oxalate by cultures of Aspergillus niger pregrown on a medium with glucose as the sole source of carbon. Glyoxylate-14C(U) was superior to glyoxylate-1-14C and citrate-1,5-14C as a source of incorporation. By addition of a great amount of citrate the accumulation of oxalate was accelerated and its maximum yield increased. In a cell-free extract from mycelium forming oxalate from citrate the enzyme oxaloacetate hydrolase (EC3.7.1.1) was identified. Its in vitro activity per flask exceeded the rate of in vivo accumulation of oxalate. Glyoxylate oxidizing enzymes (glycolate oxidase, EC1.1.3.1; glyoxylate oxidase, EC1.2.3.5;NAD(P)-dependent glyoxylate dehydrogenase; glyoxylate dehydrogenase, CoA-oxalylating, EC1.2.1.7) could not be detected in cell-free extracts. It is concluded that in cultures accumulating oxalate from citrate after pregrowth on glucose, oxalate arises by hydrolytic cleavage of oxaloacetate but not by oxidation of glyoxylate.
以葡萄糖作为唯一碳源预培养的黑曲霉菌株，可将柠檬酸-1,5-¹⁴C、乙醛酸-¹⁴C（U）或乙醛酸-1-¹⁴C中的¹⁴C整合到草酸盐中。作为整合源，乙醛酸-¹⁴C（U）优于乙醛酸-1-¹⁴C和柠檬酸-1,5-¹⁴C。添加大量柠檬酸可加速草酸盐的积累并提高其最大产量。在由柠檬酸形成草酸盐的菌丝体的无细胞提取物中，鉴定出草酰乙酸水解酶（EC3.7.1.1）。其每瓶的体外活性超过了草酸盐在体内的积累速率。在无细胞提取物中未检测到乙醛酸氧化酶（乙醇酸氧化酶，EC1.1.3.1；乙醛酸氧化酶，EC1.2.3.5；NAD（P）依赖性乙醛酸脱氢酶；乙醛酸脱氢酶，辅酶A草酰化，EC1.2.1.7）。得出的结论是，在以葡萄糖预培养后从柠檬酸盐中积累草酸盐的培养物中，草酸盐是通过草酰乙酸的水解裂解产生的，而不是通过乙醛酸的氧化产生的。
