SUBSTRATE-SPECIFICITY AND KINETICS OF CANDIDA-RUGOSA LIPASE IN ORGANIC MEDIA

The fatty acid specificity of lipase from Candida rugosa during the es terification of saturated fatty acids and sulcatol in toluene has been studied, The true kinetic parameters are obtained by fitting the expe rimental data to a Ping-Pong kinetic model that includes alcohol inhib ition. The fitted parameter values are compared with apparent values t hat would be obtained from restricted data sets in which one of the su bstrate concentrations was kept constant. It has been Sound that in re actions inhibited by alcohol the tore Ping-Pong parameters can be sign ificantly different from the apparent ones. Corrections for solvation are made by using activities instead of concentrations to Sit the kine tic parameters. Though activity coefficients, estimated using the UNIF AC group contribution method, vary by over 25% for changing concentrat ions in the same solvent, their use did not improve the fit to the dat a. This contrasts with what has been found in comparisons of different solvents, where the differences in activity coefficients are much lar ger.