过氧亚硝酸盐介导的亚铁羰基肌红蛋白氧化受一氧化碳解离的限制。
Peroxynitrite-mediated oxidation of ferrous carbonylated myoglobin is limited by carbon monoxide dissociation.
作者信息
Ascenzi Paolo, Ciaccio Chiara, Coletta Massimo
机构信息
Department of Biology and Interdepartmental Laboratory for Electron Microscopy, University Roma Tre, Viale Guglielmo Marconi 446, I-00146 Roma, Italy.
出版信息
Biochem Biophys Res Commun. 2007 Nov 30;363(4):931-6. doi: 10.1016/j.bbrc.2007.09.053. Epub 2007 Sep 24.
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)-O2) 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)x10(-2)s(-1) and k(off(CO))=(1.4+/-0.2)x10(-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.
过氧亚硝酸盐介导的亚铁亚硝基化肌红蛋白（Mb(II)-NO）氧化涉及瞬态铁亚硝基化物种（Mb(III)-NO），随后是（）NO解离并形成高铁肌红蛋白（Mb(III)）。相比之下，过氧亚硝酸盐介导的亚铁氧合肌红蛋白（Mb(II)-O2）氧化涉及瞬态亚铁脱氧和高铁衍生物（分别为Mb(II)和Mb(IV)O），随后形成Mb(III)。在此，报道了过氧亚硝酸盐介导的亚铁羰基化马心肌红蛋白（Mb(II)-CO）氧化的动力学。在pH 7.2和20.0℃下，过氧亚硝酸盐介导的Mb(II)-CO氧化（即形成Mb(III)）的一级速率常数和CO从Mb(II)-CO解离（即形成Mb(II)）的一级速率常数分别为h=(1.2±0.2)x10(-2)s(-1)和k(off(CO))=(1.4±0.2)x10(-2)s(-1)。h和k(off(CO))值的吻合表明CO解离是过氧亚硝酸盐介导的Mb(II)-CO氧化速率的限制步骤。
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