Kinetics of ferric Mycobacterium leprae truncated hemoglobin O (trHbO{single bond}Fe(III)) oxidation by H2O2 and of trHbO{single bond}Fe(IV){double bond, long}O reduction by {radical dot}NO and NO2- are reported. The value of the second-order rate constant for H2O2-mediated oxidation of trHbO{single bond}Fe(III) is 2.4 × 103 M-1 s-1. The value of the second-order rate constant for {radical dot}NO-mediated reduction of trHbO{single bond}Fe(IV){double bond, long}O is 7.8 × 106 M-1 s-1. The value of the first-order rate constant for trHbO{single bond}Fe(III){single bond}ONO decay to the resting form trHbO{single bond}Fe(III) is 2.1 × 101 s-1. The value of the second-order rate constant for NO2--mediated reduction of trHbO{single bond}Fe(IV){double bond, long}O is 3.1 × 103 M-1 s-1. As a whole, trHbO{single bond}Fe(IV){double bond, long}O, generated upon reaction with H2O2, catalyzes {radical dot}NO reduction to NO2-. In turn, {radical dot}NO and NO2- act as antioxidants of trHbO{single bond}Fe(IV){double bond, long}O, which could be responsible for the oxidative damage of the mycobacterium. Therefore, Mycobacterium leprae trHbO could be involved in both H2O2 and {radical dot}NO scavenging, protecting from nitrosative and oxidative stress, and sustaining mycobacterial respiration. © 2008 Elsevier Inc. All rights reserved.
H2O2 and {radical dot}NO scavenging by Mycobacterium leprae truncated hemoglobin O / Ascenzi, P.; De Marinis, E.; Coletta, M.; Visca, P.. - In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - ISSN 0006-291X. - 373:2(2008), pp. 197-201. [10.1016/j.bbrc.2008.05.168]
H2O2 and {radical dot}NO scavenging by Mycobacterium leprae truncated hemoglobin O
De Marinis E.;
2008
Abstract
Kinetics of ferric Mycobacterium leprae truncated hemoglobin O (trHbO{single bond}Fe(III)) oxidation by H2O2 and of trHbO{single bond}Fe(IV){double bond, long}O reduction by {radical dot}NO and NO2- are reported. The value of the second-order rate constant for H2O2-mediated oxidation of trHbO{single bond}Fe(III) is 2.4 × 103 M-1 s-1. The value of the second-order rate constant for {radical dot}NO-mediated reduction of trHbO{single bond}Fe(IV){double bond, long}O is 7.8 × 106 M-1 s-1. The value of the first-order rate constant for trHbO{single bond}Fe(III){single bond}ONO decay to the resting form trHbO{single bond}Fe(III) is 2.1 × 101 s-1. The value of the second-order rate constant for NO2--mediated reduction of trHbO{single bond}Fe(IV){double bond, long}O is 3.1 × 103 M-1 s-1. As a whole, trHbO{single bond}Fe(IV){double bond, long}O, generated upon reaction with H2O2, catalyzes {radical dot}NO reduction to NO2-. In turn, {radical dot}NO and NO2- act as antioxidants of trHbO{single bond}Fe(IV){double bond, long}O, which could be responsible for the oxidative damage of the mycobacterium. Therefore, Mycobacterium leprae trHbO could be involved in both H2O2 and {radical dot}NO scavenging, protecting from nitrosative and oxidative stress, and sustaining mycobacterial respiration. © 2008 Elsevier Inc. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
