β-N acetylhexosaminidase from Dolichos lablab seeds: Purification, biochemical characterization and interaction studies with the Dolichos lablab lectins

Abstract

Seeds of the Dolichos lablab (Indian lablab beans) have been shown by us to contain two distinct lectins, viz., glucose/mannose specific lectin (DLL-I) and a galactose specific lectin(DLL-II) that have been well characterized, hi the present study we purified (β-N-acetylhexosaminidase from these seeds by using conventional protein purification followed by Con A-Sepharose chromatography. The purified enzyme is a glycoprotein and migrates as a single band on SDS-PAGE with an apparent molecular mass of ~60 kDa. Furthermore, when the protein bodies from the seeds were isolated, the enzyme was found to be located in the protein bodies together with the lectins and other glycosidases such as the a-mannosidase. The enzyme specifically binds onto DLL-I affigel at pH 5.0 and not at pH 8.0 and showed no such interaction with the DLL-II. The protein body membrane contains a protein of 97 kDa which might possibly represent a receptor for the lectin/enzyme.