THEORETICAL-ANALYSIS OF PROTEIN-CONCENTRATION DETERMINATION USING BIOSENSOR TECHNOLOGY UNDER CONDITIONS OF PARTIAL MASS-TRANSPORT LIMITATION

The theory of a method for determining active concentration of nonpuri fied protein samples using the BIAcore biosensor technology has been d eveloped. The method relies on change in binding rate with varying how rate at high ligand concentration where mass transport from bulk to s urface with immobilized ligand becomes partially rate limiting. Prior study of binding kinetics is not necessary. If the molecular weight an d the diffusion coefficient of the analyte protein are known, no stand ard with a known concentration is required. From numeric computer simu lations a simple analytical expression for the mass transport coeffici ent derived at totally mass transport limiting conditions is shown to be applicable for conditions of partial mass transport limitation. Sim ple one to one association is assumed in deriving the method, but it i s applicable even with more complex kinetics due to a bivalent analyte or heterogeneity of analyte or ligand. (C) 1997 Academic Press.