Mechanistic studies on the dehydrogenases of methylotrophic bacteria. 2. Kinetic studies on the intramolecular electron transfer in trimethylamine and dimethylamine dehydrogenase

摘要: E.p.r. spectroscopy of the trimethylamine and dimethylamine dehydrogenases Hyphomicrobium X indicates that substrate-reduced forms these enzymes exist in triplet state, which arise through interaction a reduced [4Fe-4S] cluster flavosemiquinone, with e.p.r. signals differ detail from those dehydrogenase bacterium W3A1. Under certain conditions intramolecular electron transfer between flavoquinol form 6-S-cysteinyl-FMN all three was much slower than preceding reduction flavin to form. Trimethylamine both organisms show time-dependent broadening centred around g = 2 after mixing trimethylamine. The could be correlated an unexpected dependence rate formation state on substrate concentration. A model accounts qualitative manner for is proposed. binding enzyme seems result conformational change decreased. This finding may observation hyperbolic inhibition dehydrogenases. results indicate obligatory step catalysis suggest electrons acceptors mediated solely cluster.