Studies on substrate specificity of X-prolyl dipeptidyl-aminopeptidase during new chromogenic substrates, X-Y-p-nitroanilides

Substrate specificity of X-prolyl dipeptidyl-aminopeptidase (dipeptidyl aminopeptidase IV) was examined by using newly synthesized 8 chromogenic substrates, X-Y-p-nitroanilides. Homogeneous enzyme from human submaxillary gland hydrolyzed glycylproline p-nitroanilide almost specifically, except alanylalanine p-nitroanilide which had 11% activity.