On the specificity of chicken pancreas conjugase (gamma-glutamic acid carboxypeptidase).

The early studies on conjugase from chicken pancreas (1, 2) did not lead to the identification of this enzyme. Subsequent progress in the elucidation of the chemical structure of pteroylglutamic acid (3) and its derivatives (4, 5) left little doubt that conjugase is one of the peptidases. Pfiffner et al. (4) classified the conjugase enzymes as carboxypeptidases after they showed that the methyl ester of pteroylheptaglutamate was not attacked by conjugase, while the free acid was attacked. In the present paper the results of some experiments designed to determine the specificity of conjugase toward several suspected substrates are reported.