Transamination is the conversion of one amino acid to corresponding keto acid with simultaneous conversion of another keto acid to an amino acid. In short, it is the interconversion between a pair of amino acid and a pair of ketoacid.
All amino acids except lysine, proline, hydroxyproline, and, threonine participate in transamination. Reaction of transamination is reversible and catalyzed by enzyme aminotransferases. These enzymes are found in the cytoplasm of cells throughout the body, especially in liver, kidney, muscle, and intestine. All aminotransferases require coenzyme pyridoxal phosphate (a derivative of vitamin B6) for transamination reaction.
Transamination is the first step of amino acids catabolism in which the α-amino group of amino acid is transfer to α-ketoglutarate, and form an α-keto acid and glutamate. Glutamate can be oxidatively deaminated, or used as an amino group donor in the formation of nonessential amino acids
The two most important transamination reactions are catalyzed by alanine aminotransferase (ALT) and aspartate aminotransferase(AST).
Alanine aminotransferase enzyme, formerly called serum glutamate pyruvate transaminase (SGPT) calalyzes the transfer of amino group of alanine to α-ketoglutarate, and form pyruvate and glutamate.
Aspartate aminotransferase enzyme, formerly called serum glutamate oxaloacetate transaminase (SGOT) calalyzes the transfer of amino group of aspartate to α-ketoglutarate, and form oxaloacetate and glutamate.