Kinetics of amine modification of proteins.

A simple kinetic model for coupling small molecules such as biotin to proteins with amine-reactive reagents such as N-hydroxysuccinimide esters is developed. It predicts the reagent concentration required to modify a protein at a given concentration to a specified number of modified amines per molecule. By optimizing the model's three adjustable kinetic parameters, its predictions can be brought into close agreement with empirical data for modification of IgG, serum albumin, and other proteins over a wide range of protein and reagent concentrations. Data for modification of one protein can be used to approximate the results for modification of another protein with the same reagent under the same reaction conditions.