Title : Oxygenases without requirement for cofactors or metal ions - Fetzner_2002_Appl.Microbiol.Biotechnol_60_243
Author(s) : Fetzner S
Ref : Applied Microbiology & Biotechnology , 60 :243 , 2002
Abstract :

Mono- and dioxygenases usually depend on a transition metal or an organic cofactor to activate dioxygen, or their organic substrate, or both. This review points out that there are at least two separate families of oxygenases without any apparent requirement for cofactors or metal ions: the quinone-forming monooxygenases which are important 'tailoring enzymes' in the biosynthesis of several types of aromatic polyketide antibiotics, and the bacterial dioxygenases involved in the degradation of distinct quinoline derivatives, catalyzing the 2,4-dioxygenolytic cleavage of 3-hydroxy-4-quinolones with concomitant release of carbon monoxide. The quinone-forming monooxygenases might be useful for the modification of polyketide structures, either by using them as biocatalysts, or by employing combinatorial biosynthesis approaches. Cofactor-less oxygenases present the mechanistically intriguing problem of how dioxygen is activated for catalysis. However, the reactions catalyzed by these enzymes are poorly understood in mechanistic terms. Formation of a protein radical and a substrate-derived radical, or direct electron transfer from a deprotonated substrate to molecular oxygen to form a caged radical pair may be discussed as hypothetical mechanisms. The latter reaction route is expected for substrates that can easily donate an electron to dioxygen, and requires the ability of the enzyme to stabilize anionic intermediates. Histidine residues found to be catalytically relevant in both types of cofactor-less oxygenases might be involved in substrate deprotonation and/or electrostatic stabilization.

PubMedSearch : Fetzner_2002_Appl.Microbiol.Biotechnol_60_243
PubMedID: 12436305
Gene_locus related to this paper: artsp-hod , psepu-QDO

Related information

Gene_locus artsp-hod    psepu-QDO
Family artsp-hod    psepu-QDO    HOD-cofactorfree-dioxygenase

Citations formats

Fetzner S (2002)
Oxygenases without requirement for cofactors or metal ions
Applied Microbiology & Biotechnology 60 :243

Fetzner S (2002)
Applied Microbiology & Biotechnology 60 :243