Amino Acid Sequence of Chicken Liver Glutamate Dehydrogenase

A tryptic digest of pyridoxal 5'-phosphate-inactivated chicken liver glutamate dehydrogenase has yielded peptides accounting for 399 residues of the 503 residues in the subunit. A single peptide was isolated that contained pyridoxallysine. This peptide had a composition identical with that isolated from the bovine enzyme that was similarly treated. Cyanogen bromide peptides were isolated and used to cover those regions of the sequence for which no tryptic peptides were obtained and to obtain overlapping peptides. Data from these studies and comparisons of the sequence to that in the bovine enzyme have provided enough evidence to account for the complete amino acid sequence of chicken glutamate dehydrogenase. There are 30 differences in sequence between the bovine and chicken enzymes with most of these being conservative in nature. The most pronounced difference between the two enzymes is at the NH2 terminus where 3 additional residues occur in the chicken enzyme.