TY - JOUR
T1 - Ferricyanide-mediated oxidation of ferrous nitrosylated sperm whale myoglobin involves the formation of the ferric nitrosylated intermediate
AU - Ascenzi, Paolo
AU - Petrella, Giovanni
AU - Coletta, Massimo
PY - 2007/8/10
Y1 - 2007/8/10
N2 - Ferricyanide-mediated oxidation of ferrous oxygenated and carbonylated myoglobin (Mb(II)-O2 and Mb(II)-CO, respectively) is limited by O2 and CO dissociation, respectively, then the transient deoxygenated derivative (Mb(II)) is rapidly oxidized. Here, kinetics of ferricyanide-mediated oxidation of ferrous nitrosylated sperm whale myoblobin (Mb(II)-NO) is reported. Unlike for Mb(II)-O2 and Mb(II)-CO, ferricyanide reacts with Mb(II)-NO forming first a transient ferric nitrosylated species (Mb(III)-NO), followed by the {radical dot}NO dissociation from Mb(III)-NO. Values of the second-order rate constant for ferricyanide-mediated oxidation of Mb(II)-NO (i.e., for the formation of the transient Mb(III)-NO species) and of the first-order rate constant for {radical dot}NO dissociation from Mb(III)-NO (i.e., for Mb(III) formation) are (1.3 ± 0.2) × 106 M-1 s-1 and 7.6 ± 1.3 s-1, respectively, at pH 8.3 and 20.0 °C. Since {radical dot}NO dissociation from Mb(II)-NO is very slow, and (unlike O2 and CO) {radical dot}NO is a ligand for both Mb(II) and Mb(III), Mb(II)-NO can be oxidized without requiring {radical dot}NO dissociation.
AB - Ferricyanide-mediated oxidation of ferrous oxygenated and carbonylated myoglobin (Mb(II)-O2 and Mb(II)-CO, respectively) is limited by O2 and CO dissociation, respectively, then the transient deoxygenated derivative (Mb(II)) is rapidly oxidized. Here, kinetics of ferricyanide-mediated oxidation of ferrous nitrosylated sperm whale myoblobin (Mb(II)-NO) is reported. Unlike for Mb(II)-O2 and Mb(II)-CO, ferricyanide reacts with Mb(II)-NO forming first a transient ferric nitrosylated species (Mb(III)-NO), followed by the {radical dot}NO dissociation from Mb(III)-NO. Values of the second-order rate constant for ferricyanide-mediated oxidation of Mb(II)-NO (i.e., for the formation of the transient Mb(III)-NO species) and of the first-order rate constant for {radical dot}NO dissociation from Mb(III)-NO (i.e., for Mb(III) formation) are (1.3 ± 0.2) × 106 M-1 s-1 and 7.6 ± 1.3 s-1, respectively, at pH 8.3 and 20.0 °C. Since {radical dot}NO dissociation from Mb(II)-NO is very slow, and (unlike O2 and CO) {radical dot}NO is a ligand for both Mb(II) and Mb(III), Mb(II)-NO can be oxidized without requiring {radical dot}NO dissociation.
KW - Ferricyanide
KW - Ferricyanide-mediated oxidation
KW - Ferrous nitrosylated sperm whale myoblobin
KW - Kinetics
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U2 - 10.1016/j.bbrc.2007.05.196
DO - 10.1016/j.bbrc.2007.05.196
M3 - Article
C2 - 17562327
AN - SCOPUS:34250681370
VL - 359
SP - 871
EP - 876
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 4
ER -