Description

Members of this superfamily reduce hydrogen peroxide and oxidise a variety of organic (AH₂) and inorganic (X^-) substrates according to:
H₂O₂ + 2 AH₂ → 2 H₂O + 2 AH^. (Reaction #1)
H₂O₂ + X^- + H⁺ → H₂O + HOX (Reaction #2)

Prosthetic heme group of members of this superfamily is covalently linked with the apoprotein. By producing hypohalous acid and hypothiocianate MPO, EPO and LPO participate in unspecific immune defence and TPO in hormone biosynthesis. Numerous representatives are fusion proteins (e.g. Pxd, some Pxt, DuOx) with non-peroxidase domains.

Vertebrate peroxidase
-Eosinophil peroxidase (EPO)
-Lactoperoxidase (LPO)
-Myeloperoxidase (MPO)
-Thyroid peroxidase (TPO)
-Non mamalian vertebrate peroxidase (POX)
-Peroxidasin (Pxd)
-vascular peroxidase Peroxinectin
-Bacterial peroxicin (Pxc): some of the sequence of this group has a BACTERIOCIN function
-Invertebrate peroxinectin (Pxt)
-Short peroxidockerin (PxDo): In addition to the peroxidase, some of the sequence of this group contains a type I dockerin domain (tandem repeat of two calcium-binding loop-helix motifs, distinct from the EF-hand).

Alpha-dioxygenase (DiOx): a-Dioxygenases constitute a family of fatty acid-metabolizing enzymes only detected in plants. THese enzymes catalyze the initial step of the a-oxidation sequence. They protect plant tissues from undergoing excessive necrosis, and their activation is part of the defence mechanisms induced to protect cells from oxidative stress.

Dual oxidase (DuOx) Prostaglandin H synthase (Cyclooxygenase) (PGHS/CyOx) Linoleate diol synthase (PGHS like) (LDS): catalyzes two enzymatic reactions, viz. dioxygenation of linoleic acid into (8R)-hydroperoxylinoleate and isomerization of (8R)-hydroperoxylinoleate into (7S,8S)-dihydroxylinoleate