期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1971
卷号：68
期号：11
页码：2748-2751
DOI：10.1073/pnas.68.11.2748
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The carbohydrate-binding protein, Concanavalin A (Con A), binds to glucose- or mannose-like sites on the cell-surface membrane. Unless the cells are treated with trypsin, this protein agglutinates malignantly transformed cells, but not normal cells. The transformed cells were agglutinated at 24{degrees}C but not at 4{degrees}C. Transformed and normal cells treated with trypsin were agglutinated at both 24{degrees}C and 4{degrees}C with high concentrations of Con A (500 {micro}g/ml), but only at 24{degrees}C with low concentrations (5 {micro}g/ml). The same number of Con A molecules were bound to normal and transformed cells at both temperatures. The results indicate that the site for Con A on the surface membrane contains two activities, a component that binds Con A molecules (B) and a component that determines agglutination (A). B is not temperature sensitive and is active in normal and transformed cells, whereas A, which is temperature sensitive, is in an active form only in transformed cells. A can be activated by trypsin, and the increased activity per cell allows agglutination at 4{degrees}C with a high, but not with a low, concentration of Con A. Agglutination of transformed cells by wheat-germ agglutinin, which binds to N-acetyl-D-glucosamine-like sites, and by soybean agglutinin, which binds to N-acetyl-D-galactosamine-like sites, was not temperature sensitive. Thus, the temperature-sensitive component A is specific for Con A, and malignant transformation of normal cells, which results in agglutinability by Con A, is associated with the activation of a specific temperature-sensitive activity on the surface membrane.
