Microcoulometric analysis of trimethylamine dehydrogenase
- 1 December 1988
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 256 (2) , 657-659
- https://doi.org/10.1042/bj2560657
Abstract
Trimethylamine dehydrogenase, which contains one covalently bound 6-S-cysteinyl-FMN and one Fe4S4 cluster per subunit of molecular mass 83 000 Da, was purified to homogeneity from the methylotrophic bacterium W3A1. Microcoulometry at pH 7 in 50 mM-Mops buffer containing 0.1 mM-EDTA and 0.1 M-KCl revealed that the native enzyme required the addition of 3 reducing equivalents per subunit for complete reduction. In contrast, under identical conditions the phenylhydrazine-inhibited enzyme required the addition of 0.9 reducing equivalent per subunit with a midpoint potential of +110 mV. Least-squares analysis of the microcoulometric data obtained for the native enzyme, assuming uptake of 1 electron by Fe4S4 and 2 electrons by FMN, indicated midpoint potentials of +44 mV and +36 mV for the FMN/FMN.- and FMN.-/FMNH2 couples respectively and +102 mV for reduction of the Fe4S4 cluster.This publication has 10 references indexed in Scilit:
- Three-dimensional structure of the iron-sulfur flavoprotein trimethylamine dehydrogenase at 2.4-A resolution.Journal of Biological Chemistry, 1986
- Identity of the subunits and the stoicheiometry of prosthetic groups in trimethylamine dehydrogenase and dimethylamine dehydrogenaseBiochemical Journal, 1983
- The flavin redox-system and its biological functionPublished by Springer Nature ,1983
- Mechanistic studies on the dehydrogenases of methylotrophic bacteria. 2. Kinetic studies on the intramolecular electron transfer in trimethylamine and dimethylamine dehydrogenaseBiochemical Journal, 1982
- Mechanistic studies on the dehydrogenases of methylotrophic bacteria. 1. The influence of substrate binding to reduced trimethylamine dehydrogenase on the intramolecular electron transfer between its prosthetic groupsBiochemical Journal, 1982
- Determination of the stoichiometry of electron uptake and the midpoint reduction potentials of milk xanthine oxidase at 25.degree. by microcoulometryBiochemistry, 1982
- Participation of the iron-sulphur cluster and of the covalently bound coenzyme of trimethylamine dehydrogenase in catalysisBiochemical Journal, 1978
- Identification of the iron-sulfur center in trimethylamine dehydrogenase.Proceedings of the National Academy of Sciences, 1977
- Trimethylamine dehydrogenase from a methylotrophic bacterium I. Isolation and steady-state kineticsBiochimica et Biophysica Acta (BBA) - Enzymology, 1976
- Purification and properties of the trimethylamine dehydrogenase of Bacterium 4B6Biochemical Journal, 1974