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Updated: Oct 24, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Tresyl-mediated synthesis: kinetics of competing coupling and hydrolysis reactions as a function of pH, temperature,
J J Sperinde1, B D Martens, L G Griffith
1Massachusetts Institute of Technology, Department of Chemical Engineering, MIT 66-466, 25 Ames Street, Cambridge, Massachusetts 02139, USA.
Abstract:
Kinetic parameters have been measured for coupled nucleophilic and solvolytic reactions of 2,2,2-trifluoroethanesulfonyl (tresyl)-modified poly(ethylene glycol) based on a system of coupled differential equations implied by recently proposed elementary reaction mechanisms. Fitted kinetic parameters were found to be strong functions of pH, temperature, and steric factors. To maximize the total yield of coupled amine as well as the fraction of secondary amine linkages, our model predicts that it is desirable to run tresyl coupling reactions at low temperatures at pH approximately 8.0, depending on the amine pKa for primary, unhindered amines. For branched primary amines, our data favor room temperature at a slightly higher pH.
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