title: Kinetic analysis of Streptococcus sanguis adhesion to artificial pellicle.
abstract: Studies of equilibria between Streptococcus sanguis and artificial pellicle have suggested that there are multiple binding sites for the organism. In the present study, adhesion of S. sanguis to saliva-coated hydroxylapatite was examined by means of kinetic methods. Cell-pellicle complex formation was measured from initiation of binding to equilibrium. Rate constants were calculated for forward reactions (adsorption) and reverse reactions (desorption). Initial binding obeyed reversible, first-order kinetics, whereas desorption of bound cells followed biphasic kinetics. Initial desorption proceeded approximately ten times faster than the slower second rate. The results are consistent with the mechanism C + P reversible CP* in equilibrium with CP in which CP* represents the reversible equilibrium that shifts at a discrete rate to the high-affinity CP state. Thus, the biphasic binding behavior that has been previously deduced from equilibrium studies may be attributed to a time-dependent shift from close apposition to pellicle, stabilized by low-specificity forces, to a higher-affinity binding.
mesh_terms: D000268:Adhesiveness; D000327:Adsorption; D001665:Binding Sites; D003741:Dental Deposits / Q000503:physiopathology*; D044622:Dental Pellicle; D017886:Durapatite; D006801:Humans; D006882:Hydroxyapatites; D007700:Kinetics; D008956:Models, Chemical; D012463:Saliva / Q000502:physiology*; D013298:Streptococcus sanguis / Q000502:physiology*; D013499:Surface Properties
chemical_list: D006882:Hydroxyapatites; D017886:Durapatite