The complete amino acid sequence of mitochondrial glutamic oxaloacetic transaminase from rat liver

Abstract

The complete amino acid sequence of mitochondrial glutamic oxaloacetic transaminase from rat liver was determined. Sequence analyses were performed on the 12 cyanogen bromide peptides isolated after cleavage with cyanogen bromide. The amino acid sequences of all these cyanogen bromide peptides were determined by a combination of tryptic digestion, carboxypeptidase digestion and manual Edman degradation. The large peptides were hydrolyzed with trypsin after maleylation or treatment with 1,2-cyclohexanedione. These cyanogen bromide peptides were aligned by homology with the corresponding cyanogen bromide peptides from pig heart isozyme. The polypeptide chain has 401 amino acid residues and a calculated molecular weight of 44,358. Comparison showed that 24 of the 401 residues of mitochondrial glutamic oxaloacetic transaminase from rat liver are different from those of pig heart isozyme and that homology between the two isozymes is 94%.