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Literature summary extracted from

  • van Dalen, C.J.; Winterbourn, C.C.; Senthilmohan, R.; Kettle, A.J.
    Nitrite as a substrate and inhibitor of myeloperoxidase. Implications for nitration and hypochlorous acid production at sites of inflammation (2000), J. Biol. Chem., 275, 11638-11644.
    View publication on PubMed

Inhibitors

EC Number Inhibitors Comment Organism Structure
1.11.2.2 nitrite nitrite is an excellent inhibitor of the chlorination activity of myeloperoxidase, there is progressive inhibition of enzyme activity with increasing concentration of nitrite up to a maximum of 80%. Upon addition of 100 mM L-tyrosine, enzyme activity is completely restored Homo sapiens

Organism

EC Number Organism UniProt Comment Textmining
1.11.2.2 Homo sapiens
-
-
-

Source Tissue

EC Number Source Tissue Comment Organism Textmining
1.11.2.2 leukocyte
-
 Homo sapiens
-
1.11.2.2 neutrophil
-
 Homo sapiens
-

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1.11.2.2 Cl- + H2O2 + H+
-
 Homo sapiens HClO + H2O
-
 ?
1.11.2.2 additional information in the presence of physiological concentrations of nitrite and chloride, myeloperoxidase catalyzes little nitration of tyrosyl residues in a heptapeptide. However, the efficiency of nitration is enhanced at least 4fold by free tyrosine. Myeloperoxidase oxidizes free tyrosine to tyrosyl radicals that exchange with tyrosyl residues in peptides. These peptide radicals then couple with nitrogen dioxide to form 3-nitrotyrosyl residues Homo sapiens ?
-
 ?
1.11.2.2 nitrite + L-tyrosine + H2O2 + H+ poor substrate for myeloperoxidase, but free tyrosine facilitates nitration of tyrosyl residues by acting as a cosubstrate in the reaction Homo sapiens ?
-
 ?
1.11.2.2 thiocyanate + H2O2 + H+
-
 Homo sapiens ?
-
 ?

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
1.11.2.2 0.7
-
 nitrite at 21°C in 50 mM sodium phosphate buffer, pH 7.4 Homo sapiens
1.11.2.2 28.5
-
 Cl- at 21°C in 50 mM sodium phosphate buffer, pH 7.4 Homo sapiens
1.11.2.2 30.5
-
 thiocyanate at 21°C in 50 mM sodium phosphate buffer, pH 7.4 Homo sapiens

Cofactor

EC Number Cofactor Comment Organism Structure
1.11.2.2 heme
-
 Homo sapiens

IC50 Value

EC Number IC50 Value IC50 Value Maximum Comment Organism Inhibitor Structure
1.11.2.2 0.0013
-
 at 21°C in 50 mM sodium phosphate buffer, pH 7.4 Homo sapiens nitrite

General Information

EC Number General Information Comment Organism
1.11.2.2 physiological function at sites of inflammation myeloperoxidase will nitrate proteins, even though nitrite is a poor substrate, because the co-substrate tyrosine will be available to facilitate the reaction Homo sapiens