INFLUENCE OF SURFACE HYDROPHILIC HYDROPHOBIC BALANCE ON ENZYME PROPERTIES/

Two different enzyme surface modifications were carried out in order t o alter the protein hydrophilic/hydrophobic balance in opposite direct ions and to observe the effects induced on enzyme properties. First, a novel chemoenzymatic glycosylation method was applied, which resulted in a higher enzyme surface hydrophilic character. Then, an amphiphili c polymer, PEG, was bound to the enzymes by chemical means, and it bro ught about an increase in the global hydrophobic character. Two differ ent enzymes, a-chymotrypsin and Candida rugosa lipase, were studied, a nd in all cases, several degrees of modification were obtained. Then, the modified biocatalysts were thoroughly investigated, and the influe nce of the variation of surface hydrophilic/hydrophobic balance on hyd rolytic activity, hydrolysis kinetic parameters, synthetic activity an d thermal stability was assessed. (C) 1997 Elsevier Science B.V.