Alanine aminotransferase (ALT) is an enzymatic protein involved in catabolism of amino acids. The carbondistribution study on this clinically important protein is carried out here. The study reveals that the carbon content is generallyhigher than the expected values of 31.45%. The alteration in carbon content other than the active site might improve theactivity of this enzymatic protein. Particularly the reduction at the carboxyl end of the sequence is more appropriate. Carbondistribution analysis clearly locates the active site of ALT protein, which is reported here.