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：1976
卷号：73
期号：10
页码：3549-3553
DOI：10.1073/pnas.73.10.3549
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The kinetics of hapten binding to the homogeneous immunoglobulin A secreted by the murine plasmacytoma MOPC 460 was investigated by the chemical relaxation method. Two distinct relaxation times were observed in the binding equilibrium with three different haptens. A detailed concentration dependence analysis of relaxation times and amplitudes was performed with the hapten epsilon-N(2,4-dinitrophenyl)-lysine (Dnp-Lys). The results support a mechanism in which two interconvertible conformational states of the protein bind the hapten with different association constants. Hapten binding shifts the equilibrium towards the better binding state. These observations form kinetic evidence for a conformational transition induced in the immunoglobulin by ligand binding to its antigen binding site, and are in line with the allosteric hypothesis for the initiation of physiological functions by antigen-antibody association.
