Carbon monoxide-dependent methyl coenzyme M methylreductase in acetotrophic Methosarcina spp
Cell extracts of acetate-grown Methanosarcina strain TM-1 and Methanosarcina acetivorans both contained CH/sub 3/-S-CoM methylreductase activity. The methylreductase activity was supported by CO and H/sub 2/ but not by formate as electron donors. The CO-dependent activity was equivalent to the H/sub 2/-dependent activity in strain TM-1 and was fivefold higher than the H/sub 2/-dependent activity of M. acetivorans. When strain TM-1 was cultured on methanol, the CO-dependent activity was reduced to 5% of the activity in acetate-grown cells. Methanobacterium formicicum grown on H/sub 2/-CO/sub 2/ contained no CO-dependent methylreductase activity. The CO-dependent methylreductase of strain TM-1 had a pH optimum of 5.5 and a temperature optimum of 60/sup 0/C. The activity was stimulated by the addition of MgCl/sub 2/ and ATP. Both acetate-grown strain TM-1 and acetate-grown M. acetivorans contained CO dehydrogenase activities of 9.1 and 3.8 U/mg, respectively, when assayed with methyl viologen. The CO dehydrogenase of acetate-grown cells rapidly reduced FMN and FAD, but coenzyme F/sub 420/ and NADP/sup +/ were poor electron acceptors. No formate dehydrogenase was detected in either organism when grown on acetate. The results suggest that a CO-dependent CH/sub 3/-S-CoM methylreductase system is involved in the pathway of the conversion of acetate to methane and that free formate is not an intermediate in the pathway.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg
- OSTI ID:
- 6384429
- Journal Information:
- J. Bacteriol.; (United States), Vol. 160:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
METHANE
BIOSYNTHESIS
METHANOGENIC BACTERIA
ENZYME ACTIVITY
ACETATES
BINDING ENERGY
BIOLOGICAL PATHWAYS
CARBON MONOXIDE
COENZYMES
COMPARATIVE EVALUATIONS
CULTURE MEDIA
ELECTRONS
METHANOL
RESPONSE MODIFYING FACTORS
VALENCE
ALCOHOLS
ALKANES
BACTERIA
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACID SALTS
CHALCOGENIDES
ELEMENTARY PARTICLES
ENERGY
FERMIONS
HYDROCARBONS
HYDROXY COMPOUNDS
LEPTONS
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SYNTHESIS
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