Purification and properties of a mitogenic lectin from Lathyrus sativus seeds

A mitogenic lectin has been isolated from saline extract of Lathyrus sativus by (NH4)2SO4 precipitation, chromatography on DEAE-Sepharose and subsequent affinity chromatography on Sephadex G-100. The lectin has a molecular weight of 49,000, as determined by ultracentrifugation, and consists of heavy (Mr 19,000) and light subunits (Mr about 4,400). The amino acid composition and N-terminal sequence of both subunits are given. The lectin agglutinated human erythrocytes of different ABO groups equally well, and the agglutination is inhibited best by D-mannose and D-glucose and their alpha-methyl-glucosides. High concentrations of the lectin were needed for optimal stimulation of human lymphocytes.