CONCANAVALIN A DERIVATIVES WITH ALTERED BIOLOGICAL-ACTIVITIES
CONCANAVALIN A DERIVATIVES WITH ALTERED BIOLOGICAL-ACTIVITIES
复制标题
DOI：
10.1073/pnas.70.4.1012
复制
发表时间：
1973-01-01
影响因子：
11.1
通讯作者：
EDELMAN, GM
中科院分区：
文献类型：
--
作者：
GUNTHER, GR;WANG, JL;EDELMAN, GM
四聚体刀豆蛋白A(ConA)与琥珀酸酐或乙酸酐的化学衍生化可将蛋白质转化为二聚体分子，而不改变其与碳水化合物结合的专一性。在低浓度下，天然刀豆蛋白A和琥珀酰刀豆素A对小鼠脾细胞有丝分裂刺激的剂量-反应曲线相似。然而，当凝集素浓度超过10μg/ml时，对刀豆蛋白A的反应减弱，而对琥珀酰刀豆素A的反应直到达到更高的剂量时才减少。我们将这种差异主要归因于天然ConA分子诱导的较高的细胞死亡率。刀豆蛋白A还表现出比琥珀酰刀豆素A更强的凝集绵羊红细胞的能力和抑制免疫球蛋白受体在脾细胞上形成帽子的能力。此外，在低浓度下，刀豆蛋白A诱导其糖蛋白受体形成帽，而琥珀酰刀豆素A不诱导帽子形成。将针对ConA的抗体加入到细胞上的琥珀酰ConA，恢复了凝集、抑制免疫球蛋白受体帽子形成和诱导ConA受体帽子形成的特性。乙酰刀豆素A也得到了类似的结果。这些数据表明，琥珀酰刀豆素A和乙酰刀豆素A生物活性的改变是由于它们的价态降低所致。
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 μg/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.