It is relevant to cell physiology that nitric oxide (NO) reacts with both cytochrome oxidase (CcOX) and oxygenated myoglobin (MbO(2)). In this respect, it has been proposed [Pearce, L.L., et a]. (2002) J. Biol. Chem. 277, 13556-13562] that (i) CcOX in turnover out-competes MbO(2) for NO, and (ii) NO bound to reduced CcOX is "metabolized" in the active site to nitrite by reacting with O-2. In contrast, rapid kinetics experiments reported in this study show that (i) upon mixing NO with MbO(2) and CcOX in turnover, MbO(2) out-competes the oxidase for NO and (ii) after mixing nitrosylated CcOX with O-2 in the presence of MbO(2), NO (and not nitrite) dissociates from the enzyme causing myoglobin oxidation. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Nitric oxide, cytochrome c oxidase and myoglobin: Competition and reaction pathways / Giuffre', Alessandro; Forte, Elena; Brunori, Maurizio; Sarti, Paolo. - In: FEBS LETTERS. - ISSN 0014-5793. - 579:11(2005), pp. 2528-2532. [10.1016/j.febslet.2005.03.067]
Nitric oxide, cytochrome c oxidase and myoglobin: Competition and reaction pathways
GIUFFRE', ALESSANDRO;FORTE, Elena;BRUNORI, Maurizio;SARTI, Paolo
2005
Abstract
It is relevant to cell physiology that nitric oxide (NO) reacts with both cytochrome oxidase (CcOX) and oxygenated myoglobin (MbO(2)). In this respect, it has been proposed [Pearce, L.L., et a]. (2002) J. Biol. Chem. 277, 13556-13562] that (i) CcOX in turnover out-competes MbO(2) for NO, and (ii) NO bound to reduced CcOX is "metabolized" in the active site to nitrite by reacting with O-2. In contrast, rapid kinetics experiments reported in this study show that (i) upon mixing NO with MbO(2) and CcOX in turnover, MbO(2) out-competes the oxidase for NO and (ii) after mixing nitrosylated CcOX with O-2 in the presence of MbO(2), NO (and not nitrite) dissociates from the enzyme causing myoglobin oxidation. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
