Kinetics and Mechanisms of Peptide Aggregation I: Aggregation of a Cholecystokinin Analogue

Abstract

Aggregation kinetics for a tetrapeptide analogue of cholecystokinin (A-71623) have been studied by quasi-elastic light scattering. Aggregation kinetics were quantitated with a kinetic model, described herein, which was modified for quasi-elastic light scattering data. The model predicts that the average molecular weight of peptide aggregates increases in a linear fashion with time. Data generated for A-71623 were consistent with the model presented under conditions of varied ethanol concentration at a fixed peptide concentration, as well as varied A-71623 concentration at fixed ethanol concentration. Although not the primary thrust of this study, experimental design permitted some understanding of the effect of environmental changes on the apparent aggregation kinetics of A-71623. These studies suggest A-71623 aggregation may be partially mediated by hydrophobic bonding