Thiolate-disulfide exchange, with roles in structure, regulation, and redox processes, is a fundamental biochemical process. The mechanism of metal-assisted exchange will be presented in terms of initial rate studies (rate law), and kinetic investigations to explore how solvent (from six different solvents) influences the exchange rate. Initial rates were measured and shown to be consistent with second order kinetics, i.e., first order in metal (Zn, Au) thiolate and first order in disulfide. Results indicate that increasing the solvent dielectric from THF (ε=7.4) to DMSO (ε=46.6) increases metal-assisted exchange by a factor of 3,500. Over the same range of solvents, the rates of non-metal thiolate-disulfide exchanges decreases &gt; 5,000 times. A mechanism, incorporating recent 2D (<sup>1</sup>H-<sup>1</sup>H) ROESY NMR and DFT calculations, to explain changes in exchange rates as a function of solvent dielectric environments will be presented.

Kinetic and mechanistic investigations on metal-assisted (Zn, Au) thiolate-disulfide exchange

251st National Meeting (2016)

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