Eosinophil peroxidase

Eosinophil peroxidase is a is_associated_with::haloperoxidase is_associated_with::enzyme that in humans is encoded by the EPX is_associated_with::gene. The enzyme is a heterodimeric 71-77 kD is_associated_with::peroxidase consisting of a heavier glycosylated chain and a lighter nonglycosylated chain. This enzyme prefers is_associated_with::bromide over is_associated_with::chloride as a substrate, converting it to cytotoxic is_associated_with::hypobromite.

Function
In the presence of H2O2 formed by the is_associated_with::eosinophil, and either chloride or bromide ions, eosinophil peroxidase provides a potent mechanism by which eosinophils kill multicellular parasites (such as, for example, the nematode worms involved in is_associated_with::filariasis); and also certain is_associated_with::bacteria (such as is_associated_with::tuberculosis bacteria). Eosinophil peroxidase is a is_associated_with::haloperoxidase that preferentially uses bromide over chloride for this purpose, generating is_associated_with::hypobromite (is_associated_with::hypobromous acid). The enzyme is also capable of oxidizing is_associated_with::thiocyanate (SCN−) and uses it as a co-substrate, with optimal concentrations occurring at about normal plasma levels.

Eosinophil peroxidase is also partly responsible for tissue remodeling.

Role in pathology
The oxidizing compounds produced by eosinophil peroxidase have been implicated in the inflammatory pathology of several disease states, including is_associated_with::asthma.