EC 1.11.1.26 - NADH-dependent peroxiredoxin
IntEnz Enzyme Nomenclature
EC 1.11.1.26
Names
Reaction
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62628 [IUBMB]a hydroperoxideName origin: UniProt - CHECKED (C)Formula: HO2R
Charge: 0ChEBI compound status: CHECKED (C)H+Name origin: UniProt - CHECKED (C)Formula: H
Charge: 1ChEBI compound status: CHECKED (C)NADHName origin: UniProt - CHECKED (C)Formula: C21H27N7O14P2
Charge: -2ChEBI compound status: CHECKED (C)=an alcoholName origin: UniProt - CHECKED (C)Formula: HOR
Charge: 0ChEBI compound status: CHECKED (C)H2OName origin: UniProt - CHECKED (C)Formula: H2O
Charge: 0ChEBI compound status: CHECKED (C)
Comments:
Peroxiredoxins (Prxs) are a ubiquitous family of antioxidant proteins. They can be divided into three classes: typical 2-Cys, atypical 2-Cys and 1-Cys peroxiredoxins [1]. The peroxidase reaction comprises two steps centred around a redox-active cysteine called the peroxidatic cysteine. All three peroxiredoxin classes have the first step in common, in which the peroxidatic cysteine attacks the peroxide substrate and is oxidized to S-hydroxycysteine (a sulfenic acid). The second step of the peroxidase reaction, the regeneration of cysteine from S-hydroxycysteine, distinguishes the three peroxiredoxin classes. For typical 2-Cys Prxs, in the second step, the peroxidatic S-hydroxycysteine from one subunit is attacked by the 'resolving' cysteine located in the C-terminus of the second subunit, to form an intersubunit disulfide bond, which is then reduced by one of several cell-specific thiol-containing reductants completing the catalytic cycle. In the atypical 2-Cys Prxs, both the peroxidatic cysteine and its resolving cysteine are in the same polypeptide, so their reaction forms an intrachain disulfide bond. The 1-Cys Prxs conserve only the peroxidatic cysteine, so its regeneration involves direct interaction with a reductant molecule. This bacterial peroxiredoxin differs from most other forms by comprising two types of subunits. One subunit (AhpC) is a typical 2-Cys peroxiredoxin. Following the reduction of the substrate, one AhpC subunit forms a disulfide bond with an identical unit. The disulfide bond is reduced by the second type of subunit (AhpF). This second subunit is a flavin-containing protein that uses electrons from NADH to reduce the cysteine residues on the AhpC subunits back to their active state. Formerly EC 1.11.1.15.
Links to other databases
References
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Structure, mechanism and regulation of peroxiredoxins.Trends Biochem. Sci. 28 : 32-40 (2003). [PMID: 12517450]
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Structure, mechanism and ensemble formation of the alkylhydroperoxide reductase subunits AhpC and AhpF from Escherichia coli.Acta Crystallogr. D Biol. Crystallogr. 70 : 2848-2862 (2014). [PMID: 25372677]
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NMR studies reveal a novel grab and release mechanism for efficient catalysis of the bacterial 2-Cys peroxiredoxin machinery.FEBS J. 282 : 4620-4638 (2015). [PMID: 26402142]
[EC 1.11.1.26 created 1983 as EC 1.11.1.15, part transferred 2020 to EC 1.11.1.26]