PARTIAL PURIFICATION AND CHARACTERIZATION OF BARLEY PEPTIDE HYDROLASES

Two peptidases from germinated barley were partially purified and characterized. Recycling filtration on dextran gel was used in an improved preparative procedure. BAPA-ase (barley peptide hydrolase A) was found to be inactivated by low pH, mildly resistant to heat treatments and activated by relatively high concentrations (10-2-10-1.3 M) of Ca2+ and Mg2+. This enzyme had a very low order of substrate specificity when tested with a variety of dipeptides. It did not hydrolyze several possible protein substrates. BAEE-ase (barley peptide hydrolase B) was inactivated at high pH values, was more resistant than BAPA-ase to heat inactivation and was not activated by a variety of metal ions. This enzyme exhibited a relatively high specificity when tested with simple peptide substrates. It also did not hydrolyze proteins. Values for Km and V with alpha-N-benzoyl-l-arginine ethyl ester as substrate are given. © 1970.