Concanavalin with glycoproteins

Surolia A, Bishayee S, Ahmad A, Balasubramanian KA, Thambi-Dorai D, Poddar SK, Bacchawat BK (1975) Studies on the interaction of concanavalin A with glycoproteins. In Chowdhuri TK, Weiss AK (eds) Concanavalin A. Plenum Press, New York, London, p 95... 

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. 

Tunicamycin specifically inhibits cell division and pairing between the mating types of Tetrahymena pyriformis. The glycoproteins involved in this mating process have not yet been characterized, but may coincide with new, concanavalin A receptor-sites that appear during conjugation.495... 

Western blotting has become an important, modern technique for analysis and characterization of proteins. The procedure consists of, first, the electrophoretic transfer (blotting) of proteins from polyacrylamide gels to synthetic membranes. The transferred blots are then probed using immunological detection methods to identify proteins of specific structure and/or function. In this experiment, bovine serum will be fractionated by SDS-PAGE and the proteins blotted onto a nitrocellulose membrane. Serum glycoproteins will be identified by their specific interaction with the lectin concanavalin A. 

Concanavalin A was found by Clarke and Denborough (35) to precipitate with blood group glycoproteins from human gastric juice from two group O non-secretors and 2 group O and 3 group A secretors it... 

One of the cellobiose oxidoreductases present in S. pulverulentum has been characterised and named cellobiose oxidase (Ander and Eriksson, 1978). The enzyme contains both haem and flavin co factors and binds irreversibly to concanavalin A-Sepharose, suggesting that it is a glycoprotein. Cellobiose oxidase from S. pulverulentum has now been purified to homogeneity by Morpeth (1985). The carbohydrate and amino acid compositions of the enzyme have been determined. The enzyme contains FAD and cytochrome b prosthetic groups and is a monomer with an Mr of 74400 determined by sedimentation equilibrium. 

Allan, Auger and Crumpton used Con A-Sepharose to isolate glycoprotein cell surface receptors for concanavalin A from pig lymphocyte membranes solubilized with sodium deoxycholate [134]. 

The studies of mast cell cytokine production described above have shown that maximal induction of cytokine synthesis and release usually occurs in response to IgE-dependent activation. In common with many cell types, there is evidence that FccRI on mast cells is coupled to the phospholipase C effector system that controls two distinct signal transduction pathways, one regulated by Ca " ions and the other by protein kinase C (PKC). Exocytotic degranulation is associated with an increased cytoplasmic level of Ca ions, and activation of mast cells can be therefore achieved by the use of calcium iono-phores which raise intracellular calcium concentrations through a receptor-independent mechanism. Alternative mast cell stimuli include phorbol-12-myristate-13-acetate (PMA) which activates PKC and induces mediator secretion from basophils and rodent mast cells but not from human mast cells, and concanavalin A (Con A), a lectin which can stimulate mast cells by cross-linking of cell-bound IgE and/or cell surface glycoproteins. 

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