Dramatic hyperactivation of lipase of Thermomyces lanuginosa by a cationic surfactant: Fixation of the hyperactivated form by adsorption on sulfopropyl-sepharose

Abstract

Soluble lipase from Thermomyces lanuginosa (TLL) was dramatically hyper-activated by a cationic surfactant, cetyltrimethylammonium bromide (CTAB). The greatest hyperactivation (above 340-fold) was observed with 0.005% CTAB. In addition to that, very high hyperactivation was also observed with much higher concentrations of surfactant (100-fold in the presence of 0.3% CTAB).Without surfactant or with very low surfactant concentrations, TLL was not adsorbed to the cationic exchangers. However, in the presence of high concentrations of surfactant (0.3%), the lipase was completely and strongly adsorbed on sulfopropyl-sepharose. The adsorbed enzyme remained hyperactivated (80-fold more active than the soluble enzyme) after elimination of the excess of surfactant. Complete desorption of the hyperactivated TLL from the cationic exchanger is only achieved at 2M NaCl.The same level of hyperactivation was observed for the hydrolysis of a large substrate: fish oil. The release of EPA (eicosapentaenoic acid) was 80-fold more rapid with hyperactivated TLL derivatives than with TLL very mildly immobilized on CNBr activated agarose.Hyperactivated derivatives were very stable at 25°C and 37°C. Full activity was preserved after 1 week.