9601411 McGee Mechanisms regulating enzymatic reactions on membranes will be studied using membrane-dependent proteases as experimental model systems. The kinetics of these systems will be analyzed under biologically relevant conditions by tracer dilution techniques in continuously perfused cultures of intact cells. Effects of hydration and electrostatic forces will be investigated under controlled osmotic stress, ionic strength and temperature. Available theoretical treatments of reaction kinetics will be selected and combined on the basis of experimental data, to arrive at a general model equation. This equation will incorporate easily identifiable parameters and will have immediate practical uses in membrane research. %%% The proposed studies will provide new and fundamental information on the catalytic function of biological membranes. This information will serve to predict the role of diffusion and the consequences of colloidosmotic fluctuations on membrane-reactions in vivo. The predictive models, developed on the basis of this research, will be applicable to a large group of physiologically important protease pathways and will fill major gaps in the general understanding of mechanisms controlling reactions on surfaces. ***
