Purification and enzymatic properties of α‐galactosidase from Penicillium janthinellum

Abstract

Abstractα‐Galactosidase (E.C.3.2.1.22) from Penicillium janthinellum was purified by precipitation and fractionation with ammonium sulphate, cold acetone or ethanol, calcium phosphate gel, and column chromatographies on Sephadex G‐100 and G‐200. The enzyme was purified about 110.39‐fold when Sephadex G‐100 was used. α‐Galactosidase exhibited the optimum pH and temperature at 4.5 and 60°C, respectively. The optimum enzyme stability was obtained at pH 3.5 for 24 h (at room temperature). The enzyme was found to be thermostable below 65°C up to 40 minutes and was gradually inactivated by increasing the temperature above this degree. The MICHAELIS constant was 0.55 mM for p‐nitrophenyl‐α‐D‐galactoside. The α‐galactosidase activity was strongly inhibited by Hg++ and slightly activated by Mn++. The results show the possibility of producing a thermostable enzyme from a low‐priced agricultural product, for instance, lupine.