Fractionation of Kintoki bean lectin into isolectins.

A comprehensive study of the preparative procedure of Kintoki bean lectin resulted in the resolution of the lectin into four isolectins whose pIs varied from 5.19 to 5.67. They agglutinated human, goat, hen and mouse erythrocytes, but not those of cow. The more acidic the isolectins, the less active were the erythrocyte agglutination and the more active the stimulation of sheep lymphocytes. Although the general patterns of amino acid composition were similar, characterized by higher contents of aspartic acid, leucine and valine and lack of sulfur-containing amino acids, differences were found in a few amino acids such as phenylalanine, valine and lysine. Each lectin seems to be a tetramer of a 33,000 dalton subunit which is thought to differ in charge from lectin to lectin.