Unusual DAhydrations in anaerobic bacteria: considering ketyls (radical anions) as reactive intermediates in enzymatic reactions

FEBS Letters

Buckel, Wolfgang¹ 

[1] Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, D-35032 Marburg, Germany

关键词: DAhydratase;    (R)-2-Hydroxyglutaryl-CoA;    4-Hydroxybutyryl-CoA;    5-Hydroxyvaleryl-CoA;    1;    2-Propanediol;    Iron-sulfur cluster;    Flavin;    Coenzyme B12;    Ketyl;    Radical anion;   

DOI  :  10.1016/0014-5793(96)00530-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 B₁₂. 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).

【 授权许可】

Unknown