Dioldehydrase: an essential role for potassium ion in the homolytic cleavage of the cobalt-carbon bond in adenosylcobalamin.

ABSTRACT: The complex of dioldehydrase with adenosylcobalamin (coenzyme B12) and potassium ion reacts with molecular oxygen in the absence of a substrate to oxidize coenzyme and inactivate the complex. In this article, high performance liquid chromatography and mass spectral analysis are used to identify the nucleoside products resulting from oxygen inactivation. The product profile indicates that oxygen inactivation proceeds by direct reaction of molecular oxygen with the 5'-deoxyadenosyl radical and cob(II)alamin. Formation of 5'-peroxyadenosine as the initial nucleoside product chemically correlates this reaction with aerobic, aqueous photoinduced homolytic cleavage of adenosylcobalamin (Schwartz, P. A., and Frey, P. A., (2007) Biochemistry, in press), indicating that both reactions proceed throu

SUBMITTER: Schwartz PA 

PROVIDER: S-EPMC2516201 | biostudies-literature | 2007 Jun

REPOSITORIES: biostudies-literature