Analysis of ligand-binding data by lambda invariance testing

A method for analyzing data for one or two classes of homogeneous binding sites is presented. It uses moments of exponentially depressed data. From these the binding parameters are calculated as a function of the depression. The estimated binding constants are given by those values for which the parameters are extrema. The method needs no starting guesses for the parameters since it calculates them instead of fitting them by minimizing an objective function. The method is quick; it provides estimated binding constants with good precision and verifies the number of classes by a component incrementation test.