of elementary reaction steps, the adsorption of proteins to The interaction of proteins with surfaces is important in separasurfaces may embrace a large number of parallel and consection and purification procedures as well as in metabolism and its utive reaction steps, characterized by diverse binding forces regulation. The degree of binding to a given surface in principle (electrostatic, Lifshitz-van der Waals, Lewis acid/base) depends on the precise amino acid composition of the protein, (3). Moreover, there may be many very different equilibalthough very little is presently known about the relationship berium states under the adsorption conditions, one consequence tween amino acid sequence and binding. Here we report accurate of which is the frequently encountered mixture of competing measurements of the kinetics of adsorption of two closely homoloreversible and irreversible binding reactions. The existence gous serum albumins (human and bovine) to a hydrated metal of more than one equilibrium state, and the dependence of oxide surface, using an accurate integrated optics technique.
Marked differences between the two proteins are observed. The the observed amounts of adsorbed protein at a particular results are analyzed using a model involving two bound forms, instant on the past history of the system, has given rise to reversible and irreversible. The two forms are identified as two much confusion in the literature. Accurate knowledge of the orientations of the protein with respect to the surface which make adsorption kinetics under a given set of conditions is not differing numbers of hydrogen bonds to the surface. These numonly a prerequisite for elucidating the mechanisms of many bers were estimated on the basis of the measured desorption rate fundamental biological processes at the molecular level, but constants. The interfacial binding energy was calculated from the would also allow chromatographic retention times to be acquotient of the adsorption and desorption rate constants and comcurately predicted (4).
pared with the value calculated from surface energy available data.
General patterns governing the adsorption of proteins and
Remarkably, substitution of phosphate buffer for HEPES buffer other large molecules have yet to be convincingly identified causes dramatic changes in the adsorption, abolishing the irrevers- (5). The importance of analyzing the properties of the adible mode completely for human serum albumin. ᭧ 1997 Academic Press sorbed material and of the solid surface in the presence of a given solvent-adsorbent, surface, and solvent constituting a unique system-cannot be stressed enough. Minuscule