Pulse-chase studies of the synthesis of acetyl-CoA by carbon monoxide dehydrogenase/acetyl-CoA synthase: evidence for a random mechanism of methyl and carbonyl addition.

ABSTRACT: Carbon monoxide dehydrogenase/acetyl-CoA synthase catalyzes acetyl-CoA synthesis from CO, CoA, and a methylated corrinoid iron-sulfur protein, which acts as a methyl donor. This reaction is the last step in the Wood-Ljungdahl pathway of anaerobic carbon fixation. The binding sequence for the three substrates has been debated for over a decade. Different binding orders imply different mechanisms (i.e. paramagnetic versus diamagnetic mechanisms). Ambiguity arises because CO and CoA can each undergo isotopic exchange with acetyl-CoA, suggesting that either of these two substrates could be the last to bind to the acetyl-CoA synthase active site. Furthermore, carbonylation, CoA binding, and methyl transfer can all occur in the absence of the other two substrates. Here, we report pulse-chase stu

SUBMITTER: Seravalli J 

PROVIDER: S-EPMC2820341 | biostudies-literature | 2008 Mar

REPOSITORIES: biostudies-literature