title: Characterization of byssochlamyopeptidase A.
abstract: The enzyme properties of byssochlamyopeptidase A, a chymosin-like enzyme produced by Byssochlamys fulva were studied. The enzyme was shown to be electrophoretically and immunochemically pure. Most metallic cations had negligible effect, whereas Hg2+ greatly suppressed the enzyme activity. N-Bromosuccinimide and I2 completely inactivated the enzyme. For milk clotting at pH 4.6-6.6, the enzyme was less sensitive to pH than pepsin. The substrate specificity of the enzyme was studied by incubation of the enzyme at 37 degrees C with whole and individual casein fractions at pH 6.6 and pH 3.0, respectively. The proteolysis by the enzyme was found to be most extensive for alphas-, less for kappa-, and least for beta-casein. Studies with different synthetic dipeptides and tripeptides revealed that byssochlamyopeptidase A exhibits specificity for Phe-Tyr and Gly-Phe-Phe, but the enzyme did not hydrolyze Ac-Phe-Tyr(I2).
mesh_terms: D001203:Ascomycota / Q000201:enzymology*; D016282:Aspartic Acid Endopeptidases; D002364:Caseins; D010450:Endopeptidases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera; D007118:Immunoassay; D007700:Kinetics; D004718:Saccharomycetales / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D002364:Caseins; D007106:Immune Sera; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C019806:byssochlamyopeptidase A