PXLP-K314-GPT transaminates L-Ala to form PYR

Cytosolic glutamic-pyruvate transaminase (alanine aminotransferase) (GPT) catalyzes the reversible reaction of alanine and 2-oxoglutarate (alpha-ketoglutarate) to form pyruvate and glutamate (Sohocki et al. 1997; Yang et al. 2002). The active form of the enzyme is a dimer (Ishiguro et al. 1991) and is inferred to have a molecule of pyridoxal phosphate associated with each monomer. This reaction allows the synthesis of alanine from intermediates of glucose metabolism in a well-fed person. Under fasting conditions, alanine, derived from protein breakdown, can be converted to pyruvate and used to synthesize glucose via the gluconeogenic pathway in liver, or fully oxidized via the TCA cycle in other tissues.

细胞质谷丙转氨酶（丙氨酸氨基转移酶，GPT）催化丙氨酸与2-氧代戊二酸（α-酮戊二酸）的可逆反应，生成丙酮酸与谷氨酸（Sohocki 等人，1997年；Yang 等人，2002年）。该酶的活性形式为二聚体（Ishiguro 等人，1991年），并被推断每个单体与一个吡哆醛磷酸分子相关联。此反应允许在饱食状态下，从葡萄糖代谢的中间产物中合成丙氨酸。在禁食条件下，由蛋白质分解产生的丙氨酸可以转化为丙酮酸，并在肝脏通过糖异生途径合成葡萄糖，或在其他组织中通过三羧酸循环完全氧化。