Biosynthesis

A fitting way to finish

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Science  02 Mar 2018:
Vol. 359, Issue 6379, pp. 1005-1006
DOI: 10.1126/science.359.6379.1005-f

The cofactor heme is used by enzymes to perform challenging oxidations, including reactions on the cofactor itself. Streit et al. used spectroscopy to identify a tyrosyl radical formed during the final step of heme biosynthesis. Analysis of the reaction kinetics suggests that the radical is generated by a high-valent iron intermediate created by reaction of hydrogen peroxide with the substrate, which also serves as a cofactor in the reaction. The authors propose that the tyrosyl radical abstracts a hydrogen atom from the substrate, leading to formation of the product, heme b, by oxidative decarboxylation of the propionic acid side chains.

J. Biol. Chem. 10.1074/jbc.RA117.000830 (2018).

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