Interaction of human myeloperoxidase with nitrite

Cooper, Chris E.; Odell, Edward

doi:10.1016/0014-5793(92)81461-t

Cited by 22 publications

(9 citation statements)

References 27 publications

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“…The isosbestic points between native MPO and its nitrite complex are found at 440, 498, 594, and 650 nm. Since nitrite is a strong field ligand, a typical low spin iron complex is formed as has been confirmed by EPR spectroscopy (15). Under conditions of excess of nitrite, the pseudo first-order rate constant, k obs , was obtained from the exponential time course at 447 nm.…”

Section: Resultsmentioning

confidence: 70%

“…These data suggest similarities in complex formation of MPO with both nitrite and chloride, since the pH dependence of chloride binding exhibits a similar pattern with a pK a of about 4 (19). Since binding of both nitrite (15) and chloride (19) influences the spin state of the iron, it is reasonable to assume that the amino acid involved is the distal histidine, which, upon protonation, allows such a direct interaction between these two anions and the iron.…”

Section: Resultsmentioning

confidence: 99%

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Mechanism of Reaction of Myeloperoxidase with Nitrite

Burner¹,

Furtmüller²,

Kettle³

et al. 2000

Journal of Biological Chemistry

217

159

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Myeloperoxidase (MPO) is a major neutrophil protein and may be involved in the nitration of tyrosine residues observed in a wide range of inflammatory diseases that involve neutrophils and macrophage activation. In order to clarify if nitrite could be a physiological substrate of myeloperoxidase, we investigated the reactions of the ferric enzyme and its redox intermediates, compound I and compound II, with nitrite under pre-steady state conditions by using sequential mixing stopped-flow analysis in the pH range 4 -8. At ؊1 at pH 5. pH dependence studies suggest that both complex formation between the ferric enzyme and nitrite and nitrite oxidation by compounds I and II are controlled by a residue with a pK a of (4.3 ؎ 0.3). Protonation of this group (which is most likely the distal histidine) is necessary for optimum nitrite binding and oxidation.

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Section: Resultsmentioning

confidence: 70%

Section: Resultsmentioning

confidence: 99%

Mechanism of Reaction of Myeloperoxidase with Nitrite

Burner¹,

Furtmüller²,

Kettle³

et al. 2000

Journal of Biological Chemistry

217

159

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“…Detection of nitrite is difficult and therefore we have studied the interaction of myeloperoxidase and nitrite. Upon binding of nitrite bands at 448 nm and 625 nm appear in the visible absorption spectrum in accordance with [44]. The dissociation constant was determined at various pH values.…”

Section: Discussionmentioning

confidence: 99%

“…SC' at pH 7.4 and 8.4 X lo4 M-' . s-' at pH 9.0. Cooper et al [44] consider that the data of [55] indicate that the dissociation constant for the lactoperoxidase-nitrite complex is even larger than that of the myeloperoxidase-nitrite complex. Therefore, nitrite is unlikely to interfere in the lactoperoxidase reaction.…”

Section: Discussionmentioning

confidence: 99%

Interaction of myeloperoxidase with peroxynitrite

Floris

Piersma

Yang

et al. 1993

European Journal of Biochemistry

231

135

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Polymorphonuclear neutrophils generate both nitric oxide and superoxide and these molecules can combine to form peroxynitrite. Neutrophils also contain myeloperoxidase which reacts with peroxynitrous acid (HOONO). On mixing myeloperoxidase with HOONO compound I1 was formed. Compound I could not be detected as an intermediate. The apparent second-order rate constant of formation of compound I1 was strongly pH-dependent (2.5 X lo5 M-' . s-' at pH 8.9 and 6.2 X 106 M-' . s-' at pH 7.2). The pK, of this effect is 6.9 and it was concluded that the enzyme reacts with the protonated form of the peroxide, that is peroxynitrous acid, with a pH-independent second-order rate constant of 2.0X lo7 M-' . s-' at 12°C. The interaction of HOONO with lactoperoxidase was studied for comparison. As was observed for myeloperoxidase, compound I could not be detected as an intermediate. The apparent second-order rate constant of compound I1 formation is pH-dependent and is 3.3 X lo5 M-' . s-' at pH 7.4 and 8.4 X lo4 M-' . s-' at pH 9.0. In contrast, horseradish peroxidase reacts with HOONO to form compound I, which is subsequently followed by the formation of compound 11. The second-order rate constant for the formation of compound I is 3.2 X lo6 M-' . s-' and is pH-dependent, the pK, for this effect is 6.8. Catalase (up to 3 pM) does not affect the rate of decomposition of peroxynitrite and no compound I formation is observed. Since nitrite may be present in the peroxynitrite preparation and to discriminate between the reaction of the enzyme with nitrite or peroxynitrite, the effect of nitrite on myeloperoxidase was studied. The dissociation constant for the myeloperoxidase-nitrite complex is pH-dependent and has values of 580 pM at pH 6.0 and 55 mM at pH 8.5.Since the recent discovery that the biological activity of the endothelium-derived relaxing factor is accounted for by nitric oxide (NO) [l-31 the interest in NO has greatly increased 141. To date nitric oxide has been shown to be involved as a bioregulatory molecule in many different biological functions such as vascular smooth muscle relaxation, platelet deaggregation 151 and neural communication [6, 71. Nitric oxide is also synthesized by murine macrophages and neutrophils [8, 91 in a fashion similar to its formation in vascular endothelial cells. The molecule is synthesized from one of the two chemically equivalent terminal guanidino nitrogen atoms from L-arginine by the enzyme NO synthase, classified into two groups, constitutive and inducible, of which the constitutive enzymes are Ca2+/calmodulin-dependent [lo-131. ln contrast, the inducible NO synthase from macrophages [ 14, 151 and that from polymorphonuclear neutrophils 11 61 are calmodulin-independent, though both the inducible and the constitutive type of NO synthases are dependent on NADPH. Very recently the first NO synthase has been purified and spectroscopically characterized and has

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“…Borbely et al proposed that alpha-actinin is a target for peroxynitrite in the human myocardium; and its nitration can induce a contractile dysfunction (Borbely 2005). Additionally, an in vivo interaction might occur between the increased nitrite level and myocardial MPO, affording reactive nitrosyl derivatives (Cooper 1992) and leading to protein nitration too.…”

Section: +mentioning

confidence: 99%

Peripheral and cardiac consequences of diminished nitric oxide production

Molnár¹

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Interaction of human myeloperoxidase with nitrite

Cited by 22 publications

References 27 publications

Mechanism of Reaction of Myeloperoxidase with Nitrite

Mechanism of Reaction of Myeloperoxidase with Nitrite

Interaction of myeloperoxidase with peroxynitrite

Peripheral and cardiac consequences of diminished nitric oxide production

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