Enzymatic oxidation of substituted tryptamines catalysed by monoamine oxidase

The enzymatic deamination of 5-fl uorotryptamine and 5-hydroxytryptamine, 5-HT, catalysed by enzyme monoamine oxidase A (MAO-A, EC 1.4.3.4) was investigated using the kinetic (KIE) and solvent (SIE) isotope effects methods. The numerical values of deuterium isotope effects in the (1R) positions of 5-F-tryptamine were determined using non-competitive spectrophotomeric method. Isotopologue 5-F-[(1R)- -²H]-tryptamine, needed for kinetic studies was obtained by enzymatic decarboxylation of 5´-fl uoro-L-tryptophan, 5´-F-L-Trp, in fully deuteriated medium.