Abstract
Branched-chain amino acids (BCAAs: leucine, isoleucine, and valine) not only function as essential amino acids for protein synthesis but also regulate protein and glucose metabolism. It is very important to control the concentrations of BCAAs in order to maintain normal metabolic conditions. The human body is equipped with a system for BCAA catabolism, and this influences the concentrations of BCAAs in the body. Branched-chainα-ketoacid dehydrogenase complex (BCKDC), located at the second step of the catabolic system, is a rate-limiting enzyme of BCAA catabolism. BCKDC is regulated by covalent modification, and branched-chain α-ketoacid dehydrogenase kinase (BDK) is responsible for inactivation of the complex by phosphorylation. This review introduces studies conducted mainly by the authorʼs group and summarizes the regulation of BCAA catabolism.
