Nitrite as a substrate and inhibitor of myeloperoxidase: implications for nitration and hypochlorous acid production at sites of inflammation
CJ van Dalen, CC Winterbourn, R Senthilmohan… - Journal of Biological …, 2000 - ASBMB
Myeloperoxidase is a heme enzyme of neutrophils that uses hydrogen peroxide to oxidize
chloride to hypochlorous acid. Recently, it has been shown to catalyze nitration of tyrosine.
In this study we have investigated the mechanism by which it oxidizes nitrite and promotes
nitration of tyrosyl residues. Nitrite was found to be a poor substrate for myeloperoxidase but
an excellent inhibitor of its chlorination activity. Nitrite slowed chlorination by univalently
reducing the enzyme to an inactive form and as a consequence was oxidized to nitrogen …
chloride to hypochlorous acid. Recently, it has been shown to catalyze nitration of tyrosine.
In this study we have investigated the mechanism by which it oxidizes nitrite and promotes
nitration of tyrosyl residues. Nitrite was found to be a poor substrate for myeloperoxidase but
an excellent inhibitor of its chlorination activity. Nitrite slowed chlorination by univalently
reducing the enzyme to an inactive form and as a consequence was oxidized to nitrogen …
