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Updated: May 7, 2026

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Catalysis by desolvation: the catalytic prowess of SAM-dependent halide-alkylating enzymes
Danielle C Lohman1, David R Edwards, Richard Wolfenden
1Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina , Chapel Hill, North Carolina 27599, United States.
Abstract:
In the biological fixation of halide ions, several enzymes have been found to catalyze alkyl transfer from S-adenosylmethionine to halide ions. It proves possible to measure the rates of reaction of the trimethylsulfonium ion with I(-), Br(-), Cl(-), F(-), HO(-), and H2O in water at elevated temperatures. Comparison of the resulting second-order rate constants, extrapolated to 25 °C, with the values of k(cat)/K(m) reported for fluorinase and chlorinase indicates that these enzymes enhance the rates of alkyl halide formation by factors of 2 × 10(15)- and 1 × 10(17)-fold, respectively. These rate enhancements, achieved without the assistance of cofactors, metal ions, or general acid-base catalysis, are the largest that have been reported for an enzyme that acts on two substrates.
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