First report on a N-acetylneuraminic acid specific lectin from the marine alpheid shrimp Alpheus digitalis Complex De Haan 1844 (Crustacea: Decapoda: Alpheidae)

摘要

A 256 KDa lectin (AdL) was purified from the hemolymph of the forceps snapping shrimp Alpheus digitalis by ion-exchange chromatography, gel filtration chromatography and RP-HPLC. AdL is a pentamer with subunits of 82.4, 62.5, 51, 33, and 27.5 kDa. Hemagglutination profile and cross adsorption tests revealed a strong reactivity with rabbit erythrocytes. The agglutinating activity required Ca2+, and was reduced when the lectin was dialyzed against TBS-EDTA. The AdL was stable in a pH range (7.5-8.0) and labile at or above 68°C. Ammonium sulphate and trichloroacetic acid completely precipitated the hemagglutinating activity suggesting it is a protein. Treatment with trypsin, potassium metaperiodate oxidation of hemolymph abolished the agglutinating activity. Hemagglutination inhibition assay performed with different carbohydrates and glycoproteins revealed unique specificity of hemolymph agglutinin for N-acetylneuraminic acid and fetuin.