Receptor translational diffusion coefficient

A theoretical prediction for the receptor translational diffusion coefficient Dr based on viscous interactions of proteins with membrane lipids was derived by Saffman and Delbruck (1975). In their hydrodynamic model, a solitary cylindrical protein (i.e., a protein at infinite dilution) of radius s embedded in a membrane of thickness h and viscosity 17 m,... 

The translational diffusion coefficient (D) for small globular proteins in water at room temperature is about 10 ° m s . What might be the diffusion-controlled rate constant for encounter of such proteins with a membrane receptor or DNA target site with an encounter distance of 1 nm ... 

The results indicate that diffusion and accumulation of receptors in the contact zone is the rate-determining step and a diffusion coefficient was calculated for the receptor accumulation of between 1 and 2 x 10 m s , in close agreement with that for the lipid translational diffusion coefficient measured in vesicle membranes [10], thereby supporting earlier theoretical predictions [11]. 

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