METABOLISM OF THE BRANCHED-CHAIN AMINO ACIDS

一项对支链氨基酸新陈代谢的研究揭示了 亮氨酸在细菌中分解代谢的代谢途径 在人类身上是合成的。这条途径取决于细胞的活性 亮氨酸2，3-氨基变位酶，一种依赖腺苷钴胺的酶 作为一个辅因。在该途径中发挥作用的其他酶有 β-亮氨酸转氨酶/脱氨酶、辅酶A转移酶和硫解酶。 通过这一途径的相对碳通量和通过该途径的 不依赖钴胺极大地有利于大脑中的独立途径， 心脏、肾脏和肝脏。然而，在睾丸中，不依赖钴的 途径占碳通量的40%以上。这表明 亮氨酸的代谢可能在这个器官中起着重要的作用。 转氨酶/脱氨酶的性质将被检测和纯化 我们将尝试使用这种酶。酶活性与酶活性之间的关系 以及各种疾病状态，如恶性贫血和先天性错误 将检查新陈代谢。

A study of the metabolism of the branched-chain amino acids has revealed a pathway of metabolism of leucine that is catabolic in bacteria and appears to be synthetic in humans. The pathway depends upon the activity of the enzyme, leucine 2,3-aminomutase, an enzyme dependent upon adenosylcobalamin as a cofactor. Other enzymes which function in the pathway are Beta-leucine transaminase/deaminase, coenzyme A transferase, and thiolase. The relative carbon flux through this pathway and the pathway which is independent of cobalamin greatly favors the independent pathway in brain, heart, kidney, and liver. In the testis, however, the cobalamindependent pathway accounts for over forty percent of the carbon flux. This suggests that the metabolism of leucine may play an important role in this organ. The nature of the transaminase/deaminase will be examined and purification of the enzyme will be attempted. The relationship between enzyme activity and various disease states such as pernicious anemia and inborn errors of metabolism will be examined.