CHITIN-BINDING LECTINS FROM FUNGI

Abstract

The interaction of chitin and related saccharides with a fungal lectin (CLA) and plant lectins (WGA and STA) was studied. All these lectins are equally known to be chitin-and chitosaccharide-binding lectins, but their detailed specificities for erythrocytes and chitosaccharides were quite different from each other. WGA and STA agglutinated rabbit and sheep erythrocytes as well as human erythrocytes, whereas CLA did not. Agglutination of human erythrocytes by STA was strongly inhibited by water-soluble chitin derivatives such as ethylene glycol chitin and carboxymethyl chitin. Hemagglutination by CLA was inhibited only by ethylene glycol chitin, and that by WGA was never inhibited by these chitin derivatives. The precipitation reaction, however, occurred independently of this hemagglutination inhibition. It was observed only between ethylene glycol chitin and WGA, and not between carboxymethyl chitin and WGA, and other combinations of chitin derivatives and lectins. Water-insoluble chitin and chitosan derivatives adsorbed WGA and STA efficiently, but adsorbed CLA relatively less. The mechanism of interaction between chitosaccharides and lectins and possibility of application of these lectins to isolation and structural analysis of chitosaccharides are discussed.