ISSN:
1432-072X
Keywords:
Archaebacteria
;
Thermophiles
;
Archaeoglobus
;
Sulfate-reducing bacteria
;
F420
;
Methanofuran
;
Tetrahydromethanopterin
;
Carbon monoxide dehydrogenase
;
Acetyl-CoA/carbon monoxide dehydrogenase pathway
;
Citric acid cycle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Archaeoglobus fulgidus is an extremely thermophilic archaebacterium that can grow at the expense of lactate oxidation with sulfate to CO2 and H2S. The organism contains coenzyme F420, tetrahydromethanopterin, and methanofuran which are coenzymes previously thought to be unique for methanogenic bacteria. We report here that the bacterium contains methylenetetrahydromethanopterin: F420 oxidoreductase (20 U/mg), methenyltetrahydromethanopterin cyclohydrolase (0.9 U/mg), formyltetrahydromethanopterin: methanofuran formyltransferase (4.4 U/mg), and formylmethanofuran: benzyl viologen oxidoreductase (35 mU/mg). Besides these enzymes carbon monoxide: methyl viologen oxidoreductase (5 U/mg), pyruvate: methyl viologen oxidoreductase (0.7 U/mg), and membranebound lactate: dimethylnaphthoquinone oxidoreductase (0.1 U/mg) were found. 2-Oxoglutarate dehydrogenase, which is a key enzyme of the citric acid cycle, was not detectable. From the enzyme outfit it is concluded that in A. fulgidus lactate is oxidized to CO2 via a modified acetyl-CoA/carbon monoxide dehydrogenase pathway involving C1-intermediates otherwise only used by methanogenic bacteria.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00425174
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