Glycosidases from Cotyledons ofPisum sativumL.

Abstract

α-Mannosidase and β-N-acetylglucosaminidase were purified from extracts of cotyledons of germinating Pisum sativum L. A 13-fold purification of a-mannosidase free from β-N-acetylglucosaminidase activity was achieved by precipitation in ammonium sulphate, column chromatography on DEAE-cellulose, and treatment with 2 M pyridine. β-N-Acetylglucosaminidase was purified 200-fold by the use of (NH₄)₂SO₄, and chromatography on Concanavalin A¹-Sepharose and Sephacryl-200. This preparation showed no measurable contamination by α-mannosidase activity. Both glycosidases appear to be glycoproteins and demonstrate optimal activity at pH values of 4.0–4.5. Both glycosidases appear to have very similar molecular weights, with α-mannosidase being slightly larger than β-N-acetylglucosaminidase. An extensive search for the activity of aspartylglycosylamine amido hydrolase in pea cotyledons proved unsuccessful.