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ENZYME

ENZYME entry: EC 1.11.1.29

Accepted Name
mycoredoxin-dependent peroxiredoxin
Reaction catalysed
[mycoredoxin]-L-dithiol + a hydroperoxide <=> [mycoredoxin]-L-disulfide + an alcohol + H2O
Comment(s)
  • 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.
  • The peroxidase reaction comprises two steps centered 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.
  • Mycoredoxin-dependent enzymes are found in Mycobacteria.
  • Following the reduction of the substrate, the sulfenic acid derivative of the peroxidatic cysteine forms a protein mixed disulfide with the N-terminal cysteine of mycoredoxin, which is then reduced by the C-terminal cysteine of mycoredoxin, restoring the peroxiredoxin to active state and resulting in an intra-protein disulfide in mycoredoxin.
  • The disulfide is eventually reduced by mycothiol.
  • Formerly EC 1.11.1.15.
Cross-references
BRENDA1.11.1.29
EC2PDB1.11.1.29
ExplorEnz1.11.1.29
PRIAM enzyme-specific profiles1.11.1.29
KEGG Ligand Database for Enzyme Nomenclature1.11.1.29
IUBMB Enzyme Nomenclature1.11.1.29
IntEnz1.11.1.29
MEDLINEFind literature relating to 1.11.1.29
MetaCyc1.11.1.29
Rhea expert-curated reactions1.11.1.29
UniProtKB/Swiss-Prot
P65689, AHPE_MYCBOP9WIE2, AHPE_MYCTOP9WIE3, AHPE_MYCTU

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