Protein-protein interactions: analysis of the interaction of concanavalin A with serum glycoproteins by sedimentation equilibrium using an air-driven ultracentrifuge.
An air-driven ultracentrifuge has been used for the quantitative analysis of the interaction of concanavalin A with a number of serum glycoproteins. Concanavalin A significantly affected the sedimentation equilibrium behavior of 125I-labeled human alpha 1-acid glycoprotein, rat alpha 1-acid glycoprotein, and rat transferrin containing two N-acetylneuraminic acid residues per molecule (Tf2). The weight-average molecular weight of the labeled component increased and there was a corresponding decrease in the concentration of the labeled component at the meniscus. In contrast, concanavalin A did not significantly alter the sedimentation equilibrium behavior of the 125I-labeled rat transferrin containing three N-acetyl neuraminic acid residues per molecule. Sedimentation equilibrium results for interacting mixtures of concanavalin A and labeled glycoprotein and at various concentrations of the competitive inhibitor alpha-methyl mannoside were analyzed in terms of a model. Values of 5 X 10(4), 2 X 10(5), and 6 X 10(5) M-1 were obtained for the equilibrium constants for the interaction of concanavalin A with Tf2, human alpha 1-acid glycoprotein, and rat alpha 1-acid glycoprotein, respectively.
D055598:Chemical Phenomena; D002621:Chemistry; D003208:Concanavalin A; D006023:Glycoproteins / Q000097:blood*; D008433:Mathematics; D008956:Models, Chemical; D009961:Orosomucoid; D011485:Protein Binding; D014168:Transferrin; D014461:Ultracentrifugation / Q000295:instrumentation
D006023:Glycoproteins; D009961:Orosomucoid; D014168:Transferrin; D003208:Concanavalin A