Abstract
A fraction previously isolated from acid-treated supernatant fraction of Methanobacterium thermoautotrophicum by DEAE-Sephadex chromatography [Sauer, Mahadevan & Erfle (1984) Biochem. J. 221, 61-97] which was absolutely required for methane synthesis, has been separated into two compounds, tetrahydromethanopterin (H4MPT) and an as-yet-unidentified cofactor we call 'cytoplasmic cofactor'. H4MPT was identified by its u.v. spectrum and by 13C- and 1H-n.m.r. spectroscopy. The reduction of 2-(methylthio)ethanesulphonic acid (CH3-S-CoM) to methane by the membrane fraction from M. thermoautotrophicum was completely dependent on the addition of cytoplasmic cofactor. Methane synthesis from CO2, however, was only partially dependent on cofactor addition, and 57% of the original activity was retained in its absence. The kinetics of 14C labelling were consistent with the scheme methyl-H4MPT----CH3-S-CoM----methane, as has been proposed. This is the first time that direct experimental evidence has been presented to show that the proposed methyl transfer from H4MPT to coenzyme M (HS-CoM) actually occurs.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
