Canavalia ensiformis lectin,

A comparative study of the hemagglutinating activities of the pea (Pisum sativum), the lentil (Lens culinaris), and the jack-bean (Canavalia ensiformis) lectins towards the erythrocytes of fourteen different species showed446 that the pea and lentil lectins were, in all instances, more active than con A. Of great interest was the finding that, among these three lectins, con A alone was completely inactive against human erythrocytes (blood group, unspecified).446... 

Concanavalin A is a plant lectin from the jack bean (Canavalia ensiformis) which binds with high affinity to mannose residues of glycoproteins. Concanavalin A is known to stimulate the tyrosine kinase activity of the INSR (3-subunit with consecutive activation of kinases downstream the insulin receptor (IRS, PI 3-kinase). It is believed that Concanavalin A stimulates the activation and autophosphorylation of the INSR kinase through aggregation of the receptor, although the precise mechanism of action is unclear. 

Circular dichroism (CD) has been utilized to investigate the effect of saccharides on the conformation of lectins in solution. CD has demonstrated saccharide-induced conformational changes in the lectins from Canavalia ensiformis (7), Dolichos biflorus (8), Ricinus communis (9), and Triticum vulgaris (10). The present study uses circular dichroism to assess the secondary structure of SBA and to measure conformational transitions induced by the saccharides which bind to this lectin. These and previous studies will contribute to a clearer understanding of the unique properties of these sugar-binding proteins. 

The lectins can be conveniently divided into the legume (Fabaceae family) and nonlegume proteins. The legume lectins are exemplified by the homodimeric or homo-tetrameric, Ca2+- and Mn2+-binding and mitogenic protein concanavalin A (jackbean phytagglutinin) from Canavalia ensiformis that binds Man, Glc and Man-al-Me. 

Fig. 15.—Human IgA, Glycopeptide871 Showing the Carbohydrate-binding Loci for Various Lectins, [a. Limulus polyphemus b, Triticum vulgaris c, Ricinus communis d, Sophora japonica e, Abrus precatorius f, Cytisus sessilifolius g, Phaseolus vulgaris-, h, Canavalia ensiformis i, Lens culinaris j, Pisum sativus k, Vicia faba-, 1, Bandeiraea simplicifolia II m, Solanum tuberosum and n, Ulex europeus II.]...

Thus the lectin from Canavalia ensiformis, Concanavalin A, which has a specificity for a-D-mannopyranoside and related residues, can be purified by adsorption to Sephadex [122]. The lectin from Abrus pre-... 

Lectin from jack bean (Canavalia ensiformis)... 

These cell-agglutinating proteins have been reported active against certain membrane-containing viruses. Concanavalin A (con A, from Canavalia ensiformis) was found to inactivate HSV, vesicular stomatitis virus (VSV), influenza virus and CMV infectivity and also found to interfere with the viral replication [11]. Other examples for these toxins are lentil lectin... 

ConA 5 mg powder stock of ConA lectin from Canavalia ensiformis, 5 mg powder vial (Sigma, Saint Louis, MO). Con was reconstituted in 1 mL RPMI medium (5 mg/mL stock), aliquoted into 50-[iL fractions and stored at -20°C. 

Eectins are made up of a group of sugar-binding proteins widely found in plants and animals. Concanavalin A (Con A) is isolated from jack bean Canavalia ensiformis) and is studied extensively among lectins. Con A (molecular mass 104.000) is known to contain four identical binding... 

These proteins occur in the seeds of many plants but are especially common in the Fabaceae (Leguminosae) (more than 600 species) and the Euphorbiaceae (lectins also occur in other organisms such as fungi, bacteria, and animals). In legumes, lectins are usually found in the cotyledons (Liener, 1991). Well-known plant lectins are concanavalin A, from jack beans Canavalia ensiformis), favin, from the broad bean (Vida faba), and phasin, from the kidney bean (Phaseolus vulgaris) (Ramshaw, 1982), The toxicity of lectins differs considerably (Liener, 1991 Liener et al, 1986). Data for lectins are given in Liener et al. (1986) and Lis and Sharon (1981). 

Lectins will be represented here by concanavalin A (Con A), obtained from jack bean (Canavalia ensiformis). Con A is the best-known lectin (hemagglutinin). Its structure and mechanism of action have been studied intensively (for summaries, see Lis and Sharon, 1977,1981 Goldstein and Hayes, 1978 Koenig et al., 1982 Hardman et al., 1982), but its stability has received less attention. Doyle et al. (1976) found that metal ions protected Con A against thermal aggregation. Blund)erg and Tal (1976) observed that, under... 

Lectins are widely distributed in both the plant and animal kingdoms, and are even present in some microorganisms. The maximum amounts are found in the seeds of plants. The most frequently occurring lectins, their content and important properties are shown in Table 10.21. Some lectins traditionally have trivial names, for example the lectin (albumin) of castor seeds is ricin, and the lectin of jack beans (Canavalia ensiformis, Fabaceae) is trivially called concavalin A. 

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