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 Km 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 Vmax of enzyme was determined about 8.8 mM/min, and the Vmax decreased in the presence of codeine. The Ki of codeine was measured by using the reaction rate and the initial concentration of the inhibitor according to the Dixon plot. The Ki was found to be 0.42 mM and the IC50 of codeine was determined about 0.875 mM.