Further characterization and kinetic parameter determination of a milk-clotting protease from Mucor bacilliformis.

Further characterization of an aspartyl protease from Mucor bacilliformis with milk-clotting activity was performed. An extinction coefficient, epsilon 278 cm = 1.61 mL/mg/cm, a molecular mass of 35,400 Da and a pI of 5.2 were determined. Proteolytic activity and kinetic parameters were evaluated by using the hexapeptide Leu-Ser-pNO2-Phe-Nle-Ala-Leu-OMe as the substrate. The effect of pH and temperature on peptide cleavage, as well as protease heat stability, was determined. Such properties, taken as a whole, indicate that the M. bacilliformis protease can be considered a potential substitute for bovine chymosin in cheese manufacture.