Isotopic effects in mechanistic studies of biotransformations of fluorine derivatives of L-alanine catalysed by L-alanine dehydrogenase

Abstract

Synthesis of 3-fluoro-[2-2H]-L-alanine (3-F-[2H]-L-Ala) in reductive amination of 3-fluoropyruvic acid catalysed by L-alanine dehydrogenase (AlaDH) was described. Fluorine derivative was used to study oxidative deamination catalysed by AlaDH applied kinetic (for 3-F-L-Ala in H2O - KIE’s on Vmax: 1.1; on Vmax/KM: 1.2; for 3-F-L-Ala in 2H2O – on Vmax: 1.4; on Vmax/KM: 2.1) and solvent isotope effect methods (for 3-F-L-Ala - SIE’s on Vmax: 1.0; on Vmax/KM: 0.87; for 3-F-[2-2H]-L-Ala – on Vmax: 1.4; on Vmax/KM: 1.5). Studies explain some details of reaction mechanism.