Studies on Fungous Myrosinase

β-Glucosidase activity of fungous myrosinase was confirmed using p-nitrophenyl β-glucoside as a substrate. This activity was revealed to be due to the myrosinase itself. Experimental results indicated a resemblance of fungous myrosinase to β-glucosidases similar to plant myrosinase. The relationship between fungous and plant myrosinases to the β-glucosidases are discussed from the view of the substrate specificity of these enzymes. The conclusions are that distinction between plant and fungous myrosinases and the β-glucosidases are not as strict as previously thought, and the myrosinases should be considered β-glucosidases highly specialized for the hydrolysis of mustard oil glucoside.