**7.4 Sialic acids**

Most of Sialic acid-specific lectins was found in invertebrates such as those from the Indian horseshoe crab (Mohan et al., 1982), marine crab *Scylla serrata* (Mercy and Ravindranath, 1992), lobster, tunicalase, fungus *Hericium arinaceum* (Kawagishi et al., 1994) and leaves of mulberry (Ratanapo et al., 1998). A lectin from the white shrimp *Litopenaeus setiferus* (LsL) hemolymph is a heterotetramer of two 80 kDa and two 52 kDa subunits, *N*-acetylated sugars, such as GlcNAc, GaINAc, and NeuAc, were the most effective inhibitors of the LsL hemagglutinating activity. Desialylation of erythrocytes or inhibitory glycoproteins abolished their capacity to bind LsL, confirming the relevance of sialic acid in LsL-ligand interactions (Alpuche et al., 2005). In 2009 the *Phaseolus coccineus* lectin (PCL) specificity towards sialic acid showed the molecular mass of 30 kDa consisting of homodimer subunits. Moreover the purified PCL was devoid of antifungal activity against *Candida albicans* and Penicillium *italicum*, but markedly inhibited the growth of *Hericium maydis*, *Rhizoctonia solani*, Gibberella *sanbinetti,* and Sclerotinia *sclerotiorum* while the same concentration of PCL decrease the 50% hemagglutinating activity was inhibited by sialic acid it suggesting a significant correlation between sialic acid-specific site and its bi-functional bioactivities (Chen et al., 2009).
