Computer simulation of protein self-association during small-zone gel filtration. Estimation of equilibrium constants

Abstract

A simulation is developed that qualitatively describes the small-zone-gel-filtration behavior of a reversibly associating protein. The results reflect the dependence of the apparent MW of a reversibly associating protein on the equilibrium constant (KD) and initial concentration of the protein as well as the column length. The behavior of a protein on an individual column is characterized, and a means is provided for estimation of KD. The procedure is extended to describe the behavior of a mixture of 2 proteins capable of heterologous and homologous association. This computer simulation was applied in association studies of Ig L chains. The KD value determined for the Bence-Jones protein Au (105 M-1) is close to the value (6.6 .times. 104 M-1) determined by other methods.