Animal Lectins Research Paper

Abstract: Lectins are carbohydrate binding protein which mediate several biological function. Many studies on plant lectins are there but marine lectins are not explored that much. In this review we are focusing on the prawn/shrimp lectin. Prawn/shrimps are one of the major nutritional food at the same time it is allergic to some people because of the presence of lectin. The extraction, purification, characterisation and its biological activity of each prawn/shrimp lectin are discussed here.

Introduction

Lectins have been known from the beginning of 19th century. Agglutinin/lectins are proteins or glycoproteins which have the ability to bind to specific carbohydrates expressed on different cell surfaces and cause agglutination. This functional

Initially lectins were isolated from plants and later it turns to microorganisms and other animals. Lectin was discovered in castor beans (Ricinus communis) by Stillmark in 1888. From castor bean he extracted a toxic substance named ‘ricin’, which was capable of agglutinating human and some animal blood. An agglutinin from rabbit liver which agglutinate human or lapine erythrocytes found out in 1974 by Stockert et al is the first animal lectin. This lectin recognizes and binds asialo-glycoproteins and is responsible for their uptake and degradation by the liver. During the earlier stage of lectin discovery hemagglutination was used to represent any substance which exhibit agglutination activity (Elfstrand, 1898). When some agglutinin started to show hemagglutination activity with the human ABO blood group, the term lectin was introduced to distinguish its specificity (Boyd and

Animal lectins are initially classified into C and S type lectins based on their amino acid sequence similarity of CRD (Drickamer, 1988)(Table 1). Ca2+ is essential for carbohydrate binding in CTLs and thiol group is essential for S-type lectins. On the basis of its structure there are several families of animal lectin identified(Table 2) which include P-type lectins (phosphomannosyl receptors), C-type lectins, S-type lectins, I-type lectins(siglecs-sialic acid-binding lectin with IgG motif and others),F(fucose binding)-type, Pentraxins , (Trout) egg lectins, Discoidins, Eel agglutinin fucolectins, Annexin lectins, Fibrinogen type lectins, galectins(β-galactose-specific lectin which formerly included in the S type lectins, ERGIC-53 and VIP-36, calnexin and calreticulin ,intelectin, SUEL (sea urchin egg lectin)-type (Barondes et al. 1994;Gabius,1997;Trombetta and Helenius, 1998; Parodi, 2000; klip 2002; Lu et al. 2002, Ozeki et al. 2013),) Vasta and his colleagues (2004) reported that only some of the above mentioned lectins are present in invertebrates. Lectins from fish and marine invertebrates are mainly classified into C-type lectins (CTLs), galectins, F-type lectins, rhamnose-binding lectins (RBLs), and intelectin families. Other type lectins in marine organisms include Ricin-type, Lily-type,