These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The mechanism of adenosylcobalamin-dependent rearrangements.
    Author: Babior BM.
    Journal: Biofactors; 1988 Jan; 1(1):21-6. PubMed ID: 3076429.
    Abstract:
    Adenosylcobalamin (AdoCbl)-dependent rearrangements are a group of reactions with no obvious precedents in organic chemistry. In every case, they are characterized by a mechanism in which a hydrogen atom on one carbon atom exchanges places with a group X on an adjacent carbon: (formula; see text) Much experimental work indicates that an AdoCbl rearrangement is initiated by homolysis of the C-Co bond of the cofactor. The migrating hydrogen is then abstracted from the substrate by the resulting 5'-deoxyadenosyl radical, or by a second radical that is generated elsewhere at the active site, and, after the migration of group X, is returned to the product in a similar reaction. In at least some of the rearrangements, group X migration may occur via a cation radical intermediate that formed by the departure of X with its electrons, a process assisted by the unpaired electron left behind on the adjacent carbon after the abstraction of the migrating hydrogen. Once C-Co bond cleavage has initiated the reaction by producing a free radical at the active site, the corrin ring plays no further role in the rearrangements.
    [Abstract] [Full Text] [Related] [New Search]