人体中亮氨酸代谢的调节：一项稳定同位素研究。

Regulation of leucine metabolism in man: a stable isotope study.

作者信息

Matthews D E, Bier D M, Rennie M J, Edwards R H, Halliday D, Millward D J, Clugston G A

出版信息

Science. 1981 Dec 4;214(4525):1129-31. doi: 10.1126/science.7302583.

Abstract

Leucine catabolism is regulated by either of the first two degradative steps: (reversible) transamination to the keto acid or subsequent decarboxylation. A method is described to measure rates of leucine transamination, reamination, and keto acid oxidation. The method is applied directly to humans by infusing the nonradioactive tracer, L-[15N,1-13C]leucine. Leucine transamination was found to be operating several times faster than the keto acid decarboxylation and to be of equal magnitude in adult human males under two different dietary conditions, postabsorptive and fed. These results indicate that decarboxylation, not transamination, is the rate-limiting step in normal human leucine metabolism.

摘要

亮氨酸分解代谢由前两个降解步骤中的任何一个调节

（可逆的）转氨生成酮酸或随后的脱羧反应。本文描述了一种测量亮氨酸转氨、再氨化和酮酸氧化速率的方法。通过输注非放射性示踪剂L-[15N,1-13C]亮氨酸，该方法可直接应用于人体。研究发现，在两种不同饮食条件下（空腹和进食后）的成年男性中，亮氨酸转氨的运行速度比酮酸脱羧快几倍，且幅度相当。这些结果表明，脱羧反应而非转氨反应是正常人体亮氨酸代谢中的限速步骤。