Properties of Chitobiase and β-N-Acetylglucosaminidase from Bombyx mori L. (Lepidoptera : Bombycidae) with Special Reference to Adsorption on Chitin

Abstract

Chitobiase was purified from larval integument of Bombyx mori at apolysis by column chromatography as reported for haemolymph β-N-acetylglucosaminidase (KIMURA, 1976 a). Purification was approximately 320-fold with a yield of 11.2%, and the purified preparation had a specific activity 125 units/mg protein. The isoelectric point (pI 4.9) was more acidic than haemolymph β-N-acetylglucosaminidase (pI 5.1) and the cuticle enzyme was less stable to acetate and dilution. Binding of the cuticle enzyme on colloidal chitin was greater than the haemolymph enzyme. The yield of chitobiase by the chitin-adsorption method was about one-fourth that of chitinase.