Mitochondrial Transaminase (GOT2) in growth and metabolism of C2C12 myoblasts: Muscle glutamate dehydrogenase and GOT2 in pre-weanling mice

Glutamate can be metabolized by reacting with oxaloacetate (OAA) catalyzed by the mitochondrial form of glutamic-oxaloacetic transaminase, GOT2, generating α-ketoglutarate and aspartate. We investigated the effect of GOT2 knockout on C2C12 myoblast cell growth rates and utilization of glutamine and assessed GOT2-induced changes in cell metabolites during cell growth. Glutamate can also be metabolized by conversion to alpha-ketoglutarate catalyzed by glutamate dehydrogenase (GDH). GDH protein is barely if at all expressed in adult muscle raising the issue of the relevance of GDH in C2C12 cells. However, we found that GDH is expressed in 20-day-old, pre-weanling mice as well as in C2C12 myoblasts.

谷氨酸可与草酰乙酸（oxaloacetate, OAA）在谷草转氨酶（glutamic-oxaloacetic transaminase, GOT2）的线粒体同工型催化下发生代谢反应，生成α-酮戊二酸与天冬氨酸。本研究探究了GOT2敲除对C2C12成肌细胞生长速率及谷氨酰胺利用情况的影响，并评估了细胞生长过程中GOT2介导的细胞代谢物变化。谷氨酸还可在谷氨酸脱氢酶（glutamate dehydrogenase, GDH）催化下转化为α-酮戊二酸完成代谢。成年肌肉组织中几乎不表达GDH蛋白，即便存在表达量也极低，这引发了关于GDH在C2C12细胞中生理相关性的疑问。然而本研究发现，20日龄断奶前幼鼠与C2C12成肌细胞中均有GDH的表达。