Bovine Liver Glutamate Dehydrogenase

Glutamate dehydrogenase is reversibly inhibited by the reaction of 1 mole of pyridoxal 5'-phosphate per mole of subunit polypeptide chain of the enzyme. Reduction of the pyridoxal 5'-phosphate-inactivated enzyme with NaBH4, followed by alkylation of the thiol groups and subsequent tryptic digestion, yielded a single fluorescent peptide which after acid hydrolysis, gave approximately 1 eq of e-pyridoxyllysine. This peptide was recognized by its amino acid composition as an overlap of two tryptic peptides which had been isolated and sequenced independently. The hexadecapeptide has the sequence: Cys-Ala-Val-Val-Asp-Pro-Val-Phe-Gly-Gly-Ala-Lys*-Ala-Gly-Val-Lys.