Inhibitory Effect of Codeine on Sucrase Activity

Codeine is a common drug widely used in some countries as a pain reliever. The effect of codeine on yeast sucrase activity was studied in this report. Non-competitive inhibition was observed using double reciprocal plot. The K(m) of enzyme did not change in the presence of different concentrations of codeine (0.5- 1.5 mM) and was determined about 11.5 mM. The V(max) of enzyme was determined about 8.8 mM/min, and the V(max) decreased in the presence of codeine. The K(i) of codeine was measured by using the reaction rate and the initial concentration of the inhibitor according to the Dixon plot. The K(i) was found to be 0.42 mM and the IC(50) of codeine was determined about 0.875 mM.