PURIFICATION AND SOME PROPERTIES OF A LECTIN FROM THE SEEDS OF TRICHOSANTHES ANGUINA

A galactose-binding lectin was isolated in electrophoretically pure fo rm from the seeds of the snake gourd, Trichosanthes anguina, by affini ty chromatography on an immobilised lactose column, as well as on a cr oss-linked Guar Gum column. The lectin agglutinates native erythrocyte s of human A, B and 0 phenotypes and of rabbit, rat and mouse. The mol ecular mass of the lectin, as estimated by Sephadex G-200 gel chromato graphy, is 49 kDa. Sodium dodecyl sulphate-polyacrylamide gel electrop horesis, after reduction with beta-mercaptoethanol, revealed two polyp eptide chains linked by disulphide bonds in the lectin molecule. It co ntains no covalently linked sugars. Amino acid analysis of the lectin revealed a high content of acidic amino acids, relatively lower propor tion of basic amino acids and traces of cysteine and methionine. The l ectin has good thermal stability, and is inactivated when oxidised by metaperiodate.