PROCEDURE FOR SELECTION OF CELL WALL-ASSOCIATED GLYCOPROTEINS

A novel, sequential extraction-affinity chromatographic procedure for the selection of high mannose-type glycoproteins from the ionically bo und proteins of plant cell walls is reported. Ionically bound proteins were extracted using a modified binding buffer for Concanavalin-A, th e extract passed through Concanavalin-A Sepharose and high-mannose typ e glycoproteins selectively desorbed using alpha-methyl mannoside. Ext raction with the ConA-binding buffer compared favourably with previous ly used extraction methods in terms of the purity of peroxidase and th e range of peroxidase isozymes recovered from tobacco cell walls. The sequential affinity chromatography step cleanly selected peroxidase ac tivity and provided a significant purification via a reduction in bulk protein. This procedure has great potential as a convenient and robus t, initial step in the purification of a wide range of cell wall-assoc iated high-mannose type glycoproteins. (C) 1997 Elsevier Science Ltd.