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Unusual DAhydrations in anaerobic bacteria: considering ketyls (radical anions) as reactive intermediates in enzymatic reactions
Author(s) -
Buckel Wolfgang
Publication year - 1996
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 - 10.1016/0014-5793(96)00530-3
Subject(s) - reactive intermediate , chemistry , bacteria , enzyme , anaerobic bacteria , anaerobic exercise , biochemistry , reaction intermediate , enzyme catalysis , combinatorial chemistry , catalysis , biology , genetics , physiology
DAhydratases have been DAtected in anaerobic bacteria which use 2‐, 4‐ or 5‐hydroxyacyl‐CoA as substrates and are involved in the removal of hydrogen atoms from the unactivated β‐ or γ‐positions. In addition there are bacterial DAhydratases acting on 1,2‐diols which are substrates lacking any activating group. These enzymes contain either FAD, or flavins + iron‐sulfur clusters or coenzyme B 12 . It has been proposed that the overall DAhydrations are actually reductions followed by oxidations or vice versa mediated by these prosthetic groups. Whereas the γ‐hydrogen of 5‐hydroxyvaleryl‐CoA is activated by a transient two‐electron α,β‐oxidation, the other substrates are proposed to require either a transient one‐electron reduction or an oxidation to a ketyl (radical anion).