Effect of Buffer on Kinetics of Proton Equilibration with a Protonable Group

Menachem Gutman, Esther Nachliel, Eli Gershon

Research output: Contribution to journalArticlepeer-review


The laser-induced proton pulse generates a massive, brief, proton pulse capable of perturbing biochemical equilibria. The time resolution of the monitoring system can follow the diffusion-controlled protonation of specific sites on macfomolecular bodies [Gutman, M. (1984) Methods Biochem. Anal. 30, 1-103]. In order to apply this method in enzymology, one must first evaluate how the buffer capacity of biochemical systems (substrates and proteins) will affect the observed dynamics. Unlike equilibrium measurements, where buffer is an inert component, in kinetic studies buffer modulates the observed dynamics. In this paper we analyze the effect of buffer on the dynamics of protonation in a model system. We describe the experimental technique and introduce the mathematical formalism that determines the various rate constants involved in the reaction. The analysis of the experiments indicates that in buffered solution proton flux is carried by two mechanisms: (A) proton dissociation followed by free proton diffusion; (B) collisional proton transfer between small diffusing solutes. We demonstrate how to evaluate the contribution of each pathway to the overall proton flux.

Original languageEnglish
Pages (from-to)2937-2941
Number of pages5
Issue number12
StatePublished - 1 Jun 1985


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