Effect of surfactants on activity and stability of native and chemically modified lipases a and B from Candida rugosa

The effect of sodium dodecyl sulfate (SDS) and Triton X-100 on the hydrolytic activity of lipases A and B from Candida rugosa has been studied. Lipase B is significantly more affected than lipase A by the presence of both surfactants; Triton X-100 produces a more deleterious effect than SDS with both isoenzymes. In addition, the stability of lipases A and B in the presence of different concentrations of SDS was investigated; lipase A was more stable than isoform B. Both isoenzymes were chemically modified by reaction of their amino groups with octanoyl chloride or activated polyethylene glycol (PEG, mel. wt. 5000). In all cases the modification produced a protective effect against denaturation by SDS. In particular, PEG(5000)-lipases A and B were significantly more stable (stabilization factor: 3-4) than the native enzymes at the surfactant concentrations tested.