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6026398 
Journal Article 
Autotrophic synthesis of activated acetic acid from CO sub(2) in Methanobacterium thermoautotrophicum): Synthesis from tetrahydromethanopterin-bound C sub(1) units and carbon monoxide 
Fuchs, G; Laenge, S 
1987 
Yes 
European Journal of Biochemistry
ISSN: 0014-2956
EISSN: 1432-1033 
163 
1 
147-154 
The synthesis of acetyl-CoA from CO sub(2), H sub(2), and various C sub(1) compounds was studied in vitro with extracts and with protein fractions of Methanobacterium thermoautotrophicum). Acetyl-CoA synthesis from CO sub(2) and H sub(2) by extracts required CO sub(2) reduction to CH sub(4) to proceed. Both processes were highly stimulated by formaldehyde which served as the carbon precursor of both CH sub(4) and the CH sub(3) group of acetate. Carbon monoxide in combination with formaldehyde stimulated the acetyl-CoA synthesis up to 150-fold. In this system, which did not require CO sub(2) reduction to the formaldehyde and CO level, acetyl-CoA synthesis was not dependent on CH sub(4) formation. The soluble (100,000 x g supernatant) cell protein was resolved into a protein fraction (45-60% (NH sub(4)) sub(2)SO sub(4)-fraction) which catalyzed acetyl-CoA synthesis at a specific rate of 15 nmol multiplied by min super(-1). (equivalent of mg cell protein) super(-1) (60 degree C). This oxygen-sensitive enzyme reaction required dithioerythritol for activity and was strictly dependent on (a) coenzyme A, (b) CO, and (c) N super(5),N super(10)-methylene tetrahydromethanopterin, N super(5)-methyl tetrahydromethanopterin or formaldehyde plus tetrahydromethanopterin. The incorporation of formaldehyde is explained by the spontaneous formation of methylene tetrahydromethanopterin. 
reduction; biosynthesis; carbon dioxide; acetyl-CoA; carbon monoxide; tetrahydromethanopterin; formaldehyde; Microbiology Abstracts B: Bacteriology; Methanobacterium thermoautotrophicum; J 02732:Other cell constituents and metabolites