A phytohemagglutinin from Sunn hemp seeds (Crotalaria juncea). II. Purification by a high capacity biospecific affinity adsorbent and its physicochemical properties.

A galactose-specific lectin from seeds of Sunn Hemp (Crotalaria juncea) has been purified by fractional precipitation with ammonium sulfate followed by biospecific affinity chromatography and preparative isoelectric focusing. The adsorbent was prepared by coupling galactose to Sepharose 6B activated with divinyl sulfone. The lectin was homogeneous as judged by ultracentrifugation and by electrophoresis in cellulose acetate strips and in polyacrylamide gradient gel. Its isoelectric point is pH 8.8 and the molecular weight is about 120 000. It is a glycoprotein containing 9.8% also carbohydrate (mannose, N-acetyl-D-glucosamine, fucose, and xylose). The lectin contains 3.2 mol Ca2+, 2.2 mol Mg2+ and 0.2 mol Mn2+ per 120 000 g. No sulphur-containing amino acids were detected.