Letter to Editor
The Birth and Demise of Hypotheses on Evolution of S-Adenosyl-Lmethionine and AdenosylcobalaminPerry Allen Frey*
Department of Biochemistry, University of Wisconsin-Madison, Wisonsin, USA
- *Corresponding Author:
- Perry Allen Frey
Department of Biochemistry
University of Wisconsin-Madison
433 Babcock Drive, Madison
Wisonsin 53706, USA
Email: [email protected]
Received Date: May 21, 2017; Accepted Date: June 23, 2017; Published Date: June 26, 2017
Citation: Frey PA (2017) The Birth and Demise of Hypotheses on Evolution of S-Adenosyl-L-methionine and Adenosylcobalamin. Biochem Anal Biochem 6: 324. doi: 10.4172/2161-1009.1000324
Copyright: © 2017 Frey PA. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Relationships between adenosylcobalamin and S-adenosyl-Lmethionine (SAM)-dependent enzymatic radical reactions are explored with a view toward determining their evolutionary relationships. Adenosylcobalamin is a Vitamin B12-coenzyme, and the vitamin deficiency causes pernicious anemia in humans. Methionine, the precursor of SAM, is a nutritionally essential amino acid. Evidence implicates both SAM and adenosylcobalamin in the generation of the 5’-deoxyadenosyl radical as the initiator of carbon-centered radical chemistry. However, expectations of the evolutionary superiority of the structurally and chemically complex adenosylcobalamin as an initiator of radical biochemistry are contradicted by available information. It is pointed out that adenosylcobalamin functions equally well aerobically and anaerobically, whereas SAM requires strong reducing conditions and electron transfer mediated by a [4Fe–4S]1+ cluster to initiate carboncentered radical chemistry.