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Concanavalin A Derivatives with Altered Biological Activities
Gary R. Gunther, John L. Wang, Ichiro Yahara, Bruce A. Cunningham and Gerald M. Edelman
Proceedings of the National Academy of Sciences of the United States of America
Vol. 70, No. 4 (Apr., 1973), pp. 1012-1016
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/62412
Page Count: 5
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Chemical derivatization of tetrameric concanavalin A (Con A) with succinic anhydride or acetic anhydride converts the protein to a dimeric molecule without altering its carbohydrate-binding specificity. At low concentrations, the dose-response curves for the mitogenic stimulation of mouse spleen cells by native Con A and succinyl-Con A are similar. Above lectin concentrations of 10 μ g/ml, however, the response to Con A is diminished, while that for succinyl-Con A does not decrease until much higher doses are reached. We have attributed this difference mainly to the higher rate of cell death induced by the native Con A molecule. Con A also shows a greater capacity than succinyl-Con A to agglutinate sheep erythrocytes and to inhibit cap formation by immunoglobulin receptors on spleen cells. Moreover, at low concentrations, Con A induced its glycoprotein receptors to form caps, but succinyl-Con A did not induce cap formation. Addition of antibodies directed against Con A to succinyl-Con A bound on cells restored the properties of agglutination, inhibition of immunoglobulin receptor cap formation, and induction of cap formation by Con A receptors. Similar results have been obtained for acetyl-Con A. These data suggest that the altered biological activities of succinyl-Con A and acetyl-Con A are attributable to their reduced valence.
Proceedings of the National Academy of Sciences of the United States of America © 1973 National Academy of Sciences