The branched-chain amino acids (BCAAs) are amino acids having aliphatic side-chains with a branch, namely leucine (Leu), isoleucine (Ile) and valine (Val). They are essential amino acids and make up approximately 1/3 of skeletal muscle in the human body. BCAAs are used for strength supplementation for athletes or to aid in the recovery of burn victims. BCAAs are also involved in a wide range of other physiological effects. In addition, Leu can stimulate insulin secretion.

The Branched Chain Amino Acid (Leu/Ile/Val) Colorimetric Assay Kit provides a sensitive, simple and convenient way for detection of BCAAs in various biological fluids based on colorimetric method. The assay is based on an enzyme assay in which BCAA is oxidatively deaminated to produce NADH, which reduces the probe to generate a colored product (λmax = 450 nm). The kit can measure BCAAs in the range of 0 to 10 nmol per sample with a detection limit of ~0.2 nmol (~10 µM BCAA in sample). BCAAs in serum are about 0.1-0.4 mM each (~0.125-1.5 mM combined).