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Ferredoxin‐dependent methane formation from acetate in cell extracts of Methanosarcina barkeri (strain MS)
Author(s) -
Fischer R.,
Thauer R.K.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81195-t
Subject(s) - methanosarcina barkeri , ferredoxin , methanogenesis , chemistry , methanomicrobiales , biochemistry , strain (injury) , cofactor , methane , stereochemistry , methanosarcina , biology , enzyme , organic chemistry , anatomy
Cell extracts of Methanosarcina barkeri grown on acetate catalyzed the conversion of acetyl‐CoA to CO 2 and CH 4 at a specific rate of 50 nmol·min −1 ·mg −1 . When ferredoxin was removed from the extracts by DEAE‐Sephacel anion exchange chromatography, the extracts were inactive but full activity was restored upon addition of purified ferredoxin from M. barkeri or from Clostridiwn pasteurianum . The apparent K m for ferredoxin from M. barkeri was determined to be 2.5 μM. A ferredoxin dependence was also found for the formation of CO 2 , H 2 and methylcoenzyme M from acetyl‐CoA, when methane formation was inhibited by bromoethanesulfonate. Reduction of methyl‐coenzyme M with H 2 did not require ferredoxin. These and other data indicate that ferredoxin is involved as electron carrier in methanogenesis from acetate. Methanogenesis from acetyl‐CoA in cell extracts was not dependent on the membrane fraction, which contains the cytochromes.