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The role and source of 5′‐deoxyadenosyl radical in a carbon skeleton rearrangement catalyzed by a plant enzyme
Author(s) -
Ollagnier Sandrine,
Kervio Eric,
Rétey János
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01258-7
Subject(s) - chemistry , catalysis , datura stramonium , hyoscyamine , carbon skeleton , stereochemistry , enzyme , organic chemistry , biochemistry , botany , solanaceae , gene , biology
The last step in the biosynthesis of tropane alkaloids is the carbon skeleton rearrangement of littorine to hyoscyamine. The reaction is catalyzed by a cell‐free extract prepared from cultured hairy roots of Datura stramonium . Adenosylmethionine stimulated the rearrangement 10–20‐fold and showed saturation kinetics with an apparent K m of 25 μM. It is proposed that S ‐adenosylmethionine is the source of a 5′‐deoxyadenosyl radical which initiates the rearrangement in a similar manner as it does in analogous rearrangements catalyzed by coenzyme B 12 ‐dependent enzymes. Possible roles of S ‐adenosylmethionine as a radical source in higher plants are discussed.