Shining light on the mechanism of photochemical alkene formation in vitamin B₁₂.

ABSTRACT: A wide range of proteins and enzymes depend on alkylcobalamins (alkylCbl or vitamin B₁₂) for their activities, owing to the unique, biologically relevant Co-C bond. CarH, a regulatory protein in the bacterial carotenoid biosynthetic pathway, utilizes the photosensitivity of the Co-C bond in adenosylcobalamin (AdoCbl) for gene regulation. B₁₂-dependent reductive dehalogenases rely on chemical Co-C bond cleavage to form a Co(iii)-halide bond during catalysis. Ultrafast spectroscopy demonstrates that photolytic Co-C bond cleavage in cobalamins begins with the generation of a Co(ii) species and an alkyl radical. Interestingly, both CarH and reductive dehalogenases are thought to generate a highly reactive Co(i) species as part of their reactivity. We have used time-resolv

SUBMITTER: Mukherjee A 

PROVIDER: S-EPMC12828988 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature