The determination of equilibrium constants for heterogeneous macromolecular interactions

A method has been developed to determine the association constant for a heterogeneous association of the type A + B in equilibrium AB. This method requires knowledge of the two initial concentrations and of the resulting weight-average molecular weight for each data point. Computer simulations using Gaussian-distributed error on the measured parameters show that the researcher can readily determine whether the particular concentration range chosen is appropriate for the strength of binding and therefore how reliable the calculated constant might be. It is also shown that errors in measuring molecular weight have, in general, a more profound effect than do errors in concentration.