An unique specificity of a sialic acid binding lectin Achatinin_H, from the hemolymph of Achatina fulica snail

Abstract

A sialic acid-binding lectin, Achatinin_H, from the hemolymph of Achatina fulica snail is found to be highly specific for 9-O-acetyl sialic acid. The binding specificity of AchatininH distinguishes it from other known sialic-acid specific lectins which usually show a broader range of specificity for sialic acid. It is even better than crab lectin which shows specificity for both 4- and 9-O-acetylated derivatives of sialic acid. This limited specificity of Achatinin_H appear to account for the fact that it agglutinates only rabbit, rat and guineapig erythrocytes which contain 9-O-acetylated sialic acid but not horse (mainly contain 4-O-acetylated sialic acid), human, monkey, sheep, goat and chicken erythrocytes which contain either N-acetyl or N-glycolyl neuraminic acid but no O-acetylated derivatives. This finding was further supported by the potent inhibition of hemagglutination by free 9-O-acetylated neuraminic acid and by several glyco sphingolipids of human origin having O-acetylated sialic acid.