Partial purification of a hemagglutinin associated with cell walls from hypocotyls of Vigna radiata.

The hemagglutinin (lectin) associated with the cell walls of hypocotyls from Vigna radiata was greatly purified. At every stage in the purification the hemagglutinating activity coincided exactly with α-galactosidase activity. This suggests that, similar to the seed lectin of the same plant, both activities might be present in the same molecule which has a molecular weight of about 170,000. When the purification was performed in the absence of d-galactose and 2-mercaptoethanol (method A), the native molecule appeared to dissociate into smaller units exhibiting preferentially either α-galactosidase or lectin properties. This indicates that the subunits in the native molecule might be functionally different. The lectin appears to be bound to the cell wall and can rebind to cell walls without participation of its sugar binding sites.