Physiological and biochemical studies on germinating fungal spores V. Partial purification and characterization of trehalase in conidia of Cochliobolus miyabeanus.

Abstract

Soluble trehalase (EC 3.2.1.28) was isolated and purified from the conidia of Cochliobolus miyabeanus by diethylaminoethyl Sephadex A-50 column chromatography and polyacrylamide gel electrophoresis. The molecular weight of this enzyme was estimated to be 160000 by the gel filtration method. Although the purified trehalase hydrolyzed both trehalose and maltose, this enzyme showed higher activity toward trehalose than maltose (the Km values were 7.3×10-4M for trehalose and 1.5×10-2M for maltose). The optimal pH and temperature for the enzyme reaction were 4.0 and 37°C respectively. The enzyme became unstable at 50°C. This enzyme was competitively inhibited by fructose-6-phosphate and Na-pyruvate.