Lectins succinylation

The physicochemical and carbohydrate-binding properties of succinylated wheat-germ agglutin have been compared with those of the unmodified lectin.The dramatic decrease in the apparent number of cell-surface receptors detected using the modified lectin is discussed on the basis of a decrease in the isoelectric point of the lectin and in terms of the acidic properties of the cell surface. 

The inhibition of protein synthesis in Chinese hamster cells by diphtheria toxin is antagonized by concanavalin A, succinylated concanavalin A, and wheat germ agglutinin. The effects are reversed by methyl a-D-manno-pyranoside in the first two cases and by 2-acetamido-2-deoxy-D-glucose in the last. Thus diphtheria toxin appears to have the saccharide binding properties of a lectin. 

Phytohaemagglutinins.—Abrin, ricin, and their isolated A and B chains have been subjected to various chemical treatments and the effect of these on the biological activity of the lectins assessed. Reductive methylation, periodate oxidation, or succinylation of abrin or ricin reduced the toxicity and haemagglutinating ability of the former but not the latter. Treatment with A-acetylimidazole or A-bromosuccinimide resulted in strongly reduced toxicity of abrin and ricin, while 2-hydroxy-5-nitrobenzyl bromide had much less effect. 

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