Ledley F D, Crane A M, Klish K T, May G S
Howard Hughes Medical Institute, Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.
Biochem Biophys Res Commun. 1991 Jun 28;177(3):1076-81. doi: 10.1016/0006-291x(91)90648-q.
In most animal species and many prokaryotes, methylmalonyl CoA mutase catalyzes isomerization between methylmalonyl CoA and succinyl CoA using adenosylcobalamin as a cofactor. We describe the absence of this enzyme in Aspergillus nidulans based on the absence of enzyme activity in vitro and the failure to metabolize methylmalonate or grow in media containing this organic acid as the sole carbon source. These data contrast previous assumptions that propionate may be metabolized through propionyl CoA and methylmalonyl CoA to the TCA cycle in this organism. This is consistent with the separate evolution of these pathways in animals and lower eukaryotes due to the distinct endosymbiotic origin of their mitochondria.
在大多数动物物种和许多原核生物中，甲基丙二酰辅酶A变位酶以腺苷钴胺素作为辅因子，催化甲基丙二酰辅酶A和琥珀酰辅酶A之间的异构化反应。我们基于体外酶活性的缺失以及无法代谢甲基丙二酸或在以这种有机酸作为唯一碳源的培养基中生长，描述了构巢曲霉中这种酶的缺失。这些数据与之前认为丙酸可能通过丙酰辅酶A和甲基丙二酰辅酶A在该生物体中代谢进入三羧酸循环的假设形成对比。这与动物和低等真核生物中这些途径的独立进化相一致，因为它们线粒体的内共生起源不同。
