Calculating method and verification on IC_(50) value of tyrosinase inhibitor

Calculating methods for inhibitor concentration leading to achieve 50% inhibition(IC50)of competitive inhibitor,noncompetitive inhibitor and mixed inhibitor were derived on the basis of kinetics of enzyme inhibition.These methods were applied to calculate IC50 values of some tyrosinase inhibiting compounds,such as cinnamic acid,cinnamaldehyde and benzoic acid et al.The calculation results of competitive inhibitor,noncompetitive inhibitor and mixed inhibitor are very close to experimental data,and the average errors are 3.7%,2.4%,4.6% respectively.Such results indicates that the calculation methods are reliable.