Interspecies comparisons of aspartate aminotransferases based on terminal and active site sequences

Abstract

1. 1. N-terminal amino acid sequences of mitochondrial aspartate aminotransferases from horse heart and rat liver, and of the cytosolic isozyme from rat liver have been determined by solid phase sequencing of intact proteins. 2. 2. Evidence is presented to show that the N-terminal residue of the cytosolic isozyme from horse heart is blocked. 3. 3. C-terminal amino acid sequences of the mitochondrial isozymes from horse heart and turkey liver, and of the cytosolic isozyme from horse heart have been determined by digestion with carboxypeptidases. 4. 4. Pyridoxyl-lysine peptides have been isolated from the mitochondrial isozymes of horse heart, turkey liver and rat liver and from the cytosolic isozyme of horse heart. Sequences of these peptides have been determined. 5. 5. The results obtained are compared with those for aspartate aminotransferases from other species.