Activation and inactivation of methanol: 2-mercaptoethanesulfonic acid methyltransferase from Methanosarcina barkeri.
AUTOR(ES)
van der Meijden, P
RESUMO
Methanol is converted to methane by crude extracts of Methanosarcina barkeri. The first reaction involved in this process, is catalyzed by methanol:2-mercaptoethanesulfonic acid methyltransferase (EC 2.1.1.-). The methyltransferase has an optimum at pH 6.5 and is not inhibited by 2-bromoethanesulfonic acid. Pyridoxal-5'-phosphate acts as an inhibitor (Ki = 0.30 mM). The methyltransferase was tested in the presence of 2-bromoethanesulfonic acid, which inhibits the conversion of 2-(methylthio)ethanesulfonic acid to methane. The reaction is subject to activation and inactivation. Inactivation is brought about by the presence of oxygen, flavin mononucleotide, flavin adenine dinucleotide, and 2-(methylthio)ethanesulfonic acid, the product of the reaction. Activation of the system requires the presence of ATP and Mg2+ and of hydrogen. Hydrogen can be replaced by enzymatic systems, such as pyruvate dehydrogenase, which deliver free hydrogen.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=217335Documentos Relacionados
- Involvement of an activation protein in the methanol:2-mercaptoethanesulfonic acid methyltransferase reaction in Methanosarcina barkeri.
- Purification and properties of methanol:5-hydroxybenzimidazolylcobamide methyltransferase from Methanosarcina barkeri.
- Bioenergetics of methanogenesis from acetate by Methanosarcina barkeri.
- Characterization and purification of carbon monoxide dehydrogenase from Methanosarcina barkeri.
- Acetate assimilation pathway of Methanosarcina barkeri.
