COMPUTER-SIMULATION AND DATA-ANALYSIS OF EFFECTOR-TARGET INTERACTIONS- THE EXTRACTION OF BINDING PARAMETERS FROM EFFECTOR ACID TARGET CONJUGATE FREQUENCIES DATA BY USING LINEAR AND NONLINEAR DATA-FITTING TRANSFORMATIONS

Binding isotherms for effector-target conjugation when effector conjug ate frequencies are measured by holding constant the number of effecto r cells and by varying the number of target cells are characterized by two parameters, the maximum effector conjugate frequency, alpha(max) and gamma, which is related to the dissociation constant of the conjug ates formed, K-d. The suitability of four linear transformations of th ese binding isotherms, as well as nonlinear data-fitting techniques, t o provide estimates of alpha(max) and gamma is discussed. The strength and weakness of these procedures were investigated by calculating alp ha(max) and gamma from different sets of 100 or 500 replicate ''experi ments,'' which were generated by using an algorithm that provides nois e contributions to the conjugate frequencies with gaussian distributed errors. Both unweighted and weighted data points were used in these c alculations. A similar analysis can also be performed for binding isot herms in which target conjugate frequencies are measured at different values of effector cells by holding constant the number of target cell s. In this case, the binding isotherms are characterized by two parame ters, the maximum target conjugate frequency, beta(max) and delta, whi ch is also related to K-d. The results obtained demonstrate that ii th e experimental conditions are chosen properly, linear transformations and nonlinear fitting techniques provide reliable estimates for the bi nding parameters. Not all procedures, however, provide estimates with the same accuracy, and special emphasis to this fact must be given if the binding assays are performed at low values of the number of effect or cells. (C) 1996 Academic Press, Inc.