Three of the nine essential AAs are considered branched chain amino acids (BCAAs). They are leucine, isoleucine, and valine. This special book takes an in-depth look at the overall function of BCAAs in muscle metabolism and growth.
Three of the nine essential AAs are considered branched-chain amino acids (BCAAs). They are leucine, isoleucine, and valine. They differ from the other AAs in that their structure includes a fatty-acid (aliphatic) side chain and a branch. The actual physical structure of an AA plays a role in its action in the biological system. In physiological chemistry, the way in which the amine, a carboxylic acid group, and side chain are attached and ‘positioned’ in space, can have a particular importance to their ultimate function.
Leucine, isoleucine and valine, individually and as a group, have been reported in a number of scholarly articles as far back as 1947. Collectively, they have the most significant, anabolic effect on protein production. Some reports have gone so far as to suggest that leucine, almost exclusively, is the AA which is needed/used in the building of muscle tissue. Since all AAs are necessary for the metabolic cycle of life, it doesn’t come as any surprise that, in more recent times, this claim has come under fire. So where do BCAAs—leucine in particular—actually fit in regarding protein synthesis and muscle maintenance? What is fact and what is fiction?