The activity and enantioselectivity of lipase 1 from Candida rugosa and of a chimera enzyme obtained by replacing the lid of isoform 1 with the lid of isoform 3 were compared in organic solvents. The alcoholysis of chloro ethyl 2-hydroxy hexanoate with methanol and of vinyl acetate with 6-methyl-5-hepten-2-ol were used as model reactions in different reaction conditions. The chimera enzyme was less active and enantioselective than the wildtype in all the conditions tested. A rationale for such decreases could be that the chimera lipase has a lower proportion of enzyme molecules in the open form. This might lead to a hindered access to the enzyme active site, thus affecting the catalytic activity. (C) 2004 Wiley Periodicals, Inc.