Stoichiometry of the redox natural deamination and oxidative dehydrogenation reactions catalyzed by the radical SAM enzyme DesII

DesII from Streptomyces venezuelae is shown to consume SAM (S-adenosyl-L-methionine) versus TDP-sugar with various stoichiometries in the deamination and dehydrogenation reaction by using [Na.sub.2][S.sub.2][O.sub.4] as the reactant. The studies have not provided any evidence of an uncoupled or abortive process in the deamination reaction, as shown by the observation that dehydrogenation can take place in the absence of an external source of reductant whereas deamination cannot.