sialic acid specific lectins from episesarma tetragonum (decapoda, grapsidae): isolation, purification and characterization

two sialic acid specific lectins episesarma tetragonum agglutinin–1 and 2 were purified from the hemolymph of the mangrove crab, episesarma tetragonum . the major lectin was purified using cnbr-activated sepharose 4b conjugated to fetuin. n-acetyl glucosamine containing buffer was used for elution. the hemagglutination activity of purified lectin was inhibited by glycoproteins containing siaα, 2-3galβ, 1-4 glcnac linkages. on sds-page, the molecular weight of calcium dependent lectin was observed to be 70 kda. lectin had the maximum activity at a wide range of ph (6.5 – 9.5) and temperature (0 - 40 °c).  the physicochemical characteristics of the minor agglutinin showed that its hemagglutinating activity was calcium dependent, optimum at ph 8 – 9.5 and temperature 0 – 37 °c. the only potent inhibitor of minor lectin was bovine submaxillary mucin. an attempt was also made to purify minor lectin by affinity chromatography using bovine submaxillary mucin coupled to cnbr-activated sepharose 4b column. the lectin was eluted with elution buffer containing ethylene diamine tetra acetate. strong inhibition of purified minor lectin by bovine submaxillary mucin and non-inhibitory action of de-o-acetylated bovine submaxillary mucin suggested that the lectin was o-acetyl sialic acid specific.