Alteration in the Composition of β-Lectins Caused by Chemical and Enzymic Attack

Abstract

Variation in the conditions of extraction of β-lectins from a number of seeds and plant tissues resulted in differences in the amino acid composition and the protein content of the isolated product. These differences may be due to differential extraction of the β-lectin, degradative losses of protein or carbohydrate components of the β-lectin, or a combination of these possibilities. Subtilisin treatment of the Alocasia macrorrhizos β-lectin removes 80% of the protein and the material remaining after enzymic treatment retains the capacity to bind to the Yariv artificial antigen. A number of β-lectins were treated with subtilisin and the amino acid compositions of the residual material were similar, with high contents of hydroxyproline, alanine and serine. The amino acid composition of the Phaseolus lunatus β-lectin was not altered by β-elimination. The capacity of the β-lectin to bind to the Yariv artificial antigens was eliminated by progressive acid hydrolysis under conditions where both glycosidic and peptide linkages may be labile.