Peroxynitrite-mediated oxidation of ferrous nitrosylated myoglobin (Mb(II)-NO) involves the transient ferric nitrosylated species (Mb(III)-NO), followed by NO dissociation and formation of ferric myoglobin (Mb(III)). In contrast, peroxynitrite-mediated oxidation of ferrous oxygenated myoglobin (Mb(II)-O-2) involves the transient ferrous deoxygenated and ferryl derivatives (Mb(II) and Mb(IV)=O, respectively), followed by Mb(III) formation. Here, kinetics of peroxynitrite-mediated oxidation of ferrous carbonylated horse heart myoglobin (Mb(II)-CO) is reported. Values of the first-order rate constant for peroxynitrite-mediated oxidation of Mb(II)-CO (i.e., for Mb(III) formation) and of the first-order rate constant for CO dissociation from Mb(II)-CO (i.e., for Mb(II) formation) are h = (1.2 +/- 0.2) x 10(-2) s(-1) and k(off(CO)) = (1.4 +/- 0.2) x 10(-2) s(-1) , respectively, at pH 7.2 and 20.0 degrees C. The coincidence of values of h and k(off(CO)) indicates that CO dissociation represents the rate limiting step of peroxynitrite-mediated oxidation of Mb(II)-CO. (C) 2007 Elsevier Inc. All rights reserved.
Ascenzi, P., Ciaccio, C., Coletta, M. (2007). Peroxynitrite-mediated oxidation of ferrous carbonylated myoglobin is limited by carbon monoxide dissociation. BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 363(4), 931-936 [10.1016/j.bbre.2007.09.053].
Peroxynitrite-mediated oxidation of ferrous carbonylated myoglobin is limited by carbon monoxide dissociation
COLETTA, MASSIMILIANO
2007-01-01
Abstract
Peroxynitrite-mediated oxidation of ferrous nitrosylated myoglobin (Mb(II)-NO) involves the transient ferric nitrosylated species (Mb(III)-NO), followed by NO dissociation and formation of ferric myoglobin (Mb(III)). In contrast, peroxynitrite-mediated oxidation of ferrous oxygenated myoglobin (Mb(II)-O-2) involves the transient ferrous deoxygenated and ferryl derivatives (Mb(II) and Mb(IV)=O, respectively), followed by Mb(III) formation. Here, kinetics of peroxynitrite-mediated oxidation of ferrous carbonylated horse heart myoglobin (Mb(II)-CO) is reported. Values of the first-order rate constant for peroxynitrite-mediated oxidation of Mb(II)-CO (i.e., for Mb(III) formation) and of the first-order rate constant for CO dissociation from Mb(II)-CO (i.e., for Mb(II) formation) are h = (1.2 +/- 0.2) x 10(-2) s(-1) and k(off(CO)) = (1.4 +/- 0.2) x 10(-2) s(-1) , respectively, at pH 7.2 and 20.0 degrees C. The coincidence of values of h and k(off(CO)) indicates that CO dissociation represents the rate limiting step of peroxynitrite-mediated oxidation of Mb(II)-CO. (C) 2007 Elsevier Inc. All rights reserved.File | Dimensione | Formato | |
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