Stabilization of Crystalline Acid Carboxypeptidase from Penicillium janthinellum by Nonionic Surfactants, and Inhibition of Enzyme Activity by Anionic Compounds

Abstract

The crystalline acid carboxypeptidase from Penicillium janthinellum IFO-8070 was stabilized by the addition of nonionic surfactants, such as Triton X-100, Brij 35, Span 40, and Tween 20. In the presence of these stabilizers, extremely diluted enzyme (0.3 μg/ml of 50mM sodium acetate buffer, pH 3.7) was almost completely stable after 2 days incubation at 25°C. About 35%. and 20% of the enzyme activities were activated by the addition of Triton X-100 and Brij 35, respectively. Triton X-100 completely retarded inactivation at freezing (-15°C). On the other hand, anionic surfactants of SLS and LBSA, and cationic surfactant of cetyltrimethylammonium bromide strongly inactivated the enzyme. The inhibition of the fatty acid series was roughly proportional to the molecular weight of the inhibitor. Di-, and Tri-carboxylic acids also inhibited the enzyme activity.