Canavalia ensiformis

The chief sources of this important enzyme are (a) the jack bean (Canavalia ensiformis). (b) the soy (or soja) bean (Glycine hispida). The enzyme is of great value in identifying and estimating urea. The action of urease on urea is specific, the reaction catalysed being ... 

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. 

Enzymatic mannosylation of the alkaloids by a-mannosidase from Canavalia ensiformis (Jack beans) was accomplished via two different strategies - transglycosylation using p-nitrophenyl-a-D-mannopyranoside or reversed glycosylation using a high concentration of mannose [46] (Fig. 10). 

Betancur-Ancona, D., Chel-Guerrero, L., Canizares-Hernandez, E. (1997). Acetylation and characterization of Canavalia ensiformis starch. J. Agric. Food Chem., 45, 378-382. 

Canaline is a potent inhibitor of all seven pyridoxal phosphate-containing enzymes studied by Rahiala et (27) but it lacks adverse effects on three ornithine-utiTTzing enzymes lacking a Bg cofactor. Finally, in jack bean, Canavalia ensiformis, ornithine carbamoyl transferase can form 0-ureido-L-homoserine from canaline and carbamoyl phosphate as it does citrulline from ornithine and carbamoyl phosphate. Nevertheless, neither compound inhibited formation of the reaction products (31). 

When bovine-comeal, peptido-keratan sulfate was degraded chemically, a tetrasaccharide fraction was obtained, and the sequence in this was determined from the hydrolytic pattern with E. coli jS-D-galactosidase, Canavalia ensiformis a-D-mannosidase (EC 3.2.1.24), human-placental / -D-mannosidase, and bovine-kidney a-L-fucosidase. 72... 

Fig. 1. Optical absorption spectra of urease from jack bean (Canavalia ensiformis). (A) Enzyme, 43.3 mg/ml in 1 mM /i-mercaptoethanol/1 mM EDTA (B) with 10 mM acetohydroxamic acid (C) urease, 11.9 mg/ml after acidification, pH 3.8 (C ) after 2 hours at pH 3.8 the latter enzyme retained 6.1% of its original activity. Redrawn, with permission, from Ref. I.

The jack beans grown in Japan, Canavalia ensiformis var. gladiata, present special problems in the isolation procedure. Hanabusa (18) has proposed a modified procedure for extraction without the use of acetone. 

Horse bean Canavalia ensiformis Rodriguez-Kabanaetal., 1992b... 

Rodriguez-Kdbana, R., Pinochet, J., Robertson, D.G, Weaver, C.F., King, P.S. Horsebean (Canavalia ensiformis) and crotalaria (Crotalaria spectabilis) for the management of Meloidogyne spp. Nematropica 1992b 22 29-35. 

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. 

It has not been possible so far to establish that Cr is an essential element required by plants, however, addition of Cr to soils deficient in the element has been shown to increase growth rates and yields of potatoes, maize, rye, wheat or oats (Scharrer and Schropp, 1935 Huffman and Allaway, 1973 Bertrand and De Wolf, 1986). Nickel appears to be an essential element for plants (Farago and Cole, 1988). Zerner and coworkers (Dixon et al., 1975) demonstrated that urease isolated from jack bean (Canavalia ensiformis) was a nickel enzyme. Eskew et al. (1983) have shown that Ni is an essential micronutrient for legumes. Most plants contain nickel in the range 1 - 6 mg kg-1 (Vanselow, 1966 Hutchinson, 1981). The uptake of Ni is enhanced by low pH values, and available nickel increases at pH less than 6.5 as a consequence of the breakdown of Ni complexes in the soil with Fe and Mn oxides. Uptake of nickel by plants and questions of toxicity and tolerance have been reviewed by Farago and Cole (1988). Nickel toxicity toward plants has been reviewed by Vanselow (1966) and Hutchinson (1981). 

L-Canavanine (88), a nonprotein amino acid in legumes such as jack bean (Canavalia ensiformis (L.) DC.), has been shown to inhibit growth of susceptible plant species.53 L-3,4-Dihydroxyphenylalanine (l-DOPA, 89) has been isolated as an allelochemical from a cover crop, velvet bean (Mucuna pruriens (L.) DC. var. utilis).54... 

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. 

Canavalia ensiformis Canavalia ensiformis (jack bean) Man, Glc, Man-a-l-Me... 

Canavalia concanavalin B Canavalia ensiformis (jackbean) Chitinase-homologue... 

L-Canaline (= 2-Amino-4- Canavalia ensiformis (jackbean) (aminoxy)butyric acid) (Fabaceae) [seed]... 

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... 

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.]...

---