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 bound proteins of plant cell walls is reported. Ionically bound proteins were extracted using a modified binding buffer for Concanavalin-A, the extract passed through Concanavalin-A Sepharose and high-mannose type glycoproteins selectively desorbed using alpha-methyl mannoside. Extraction with the ConA-binding buffer compared favourably with previously used extraction methods in terms of the purity of peroxidase and the range of peroxidase isozymes recovered from tobacco cell walls. The sequential affinity chromatography step cleanly selected peroxidase activity and provided a significant purification via a reduction in bulk protein. This procedure has great potential as a convenient and robust, initial step in the purification of a wide range of cell wall-associated high-mannose type glycoproteins. (C) 1997 Elsevier Science Ltd.