Study on enzymatic characteristics of cathepsin L from yak meat

Cathepsin L was extracted from Longissimusdorsi of yak and studied on its enzymatic characteristics.Results indicated that optimum pH and temperature of the enzyme for hydrolysis of substrate specificity Z-Phe-Arg-AMC were pH5.5 and 40℃.It was high stable at pH5.0 ～ 6.0 and 40 ～ 50℃.The appropriate reaction time and substrate concentration were 30min and 25μmol/L, respectively.Metal ions including Ca2+、Cu2+、Mn2+、K+、Fe2+、Fe3+and Zn2+inhibited the enzyme in various degree.The enzyme was partially inhibited by EDTA and EGTA while L-Cys and β-ME could increase the activity of the protease.