Chemistry Reference
In-Depth Information
TABLE 5.11. Rate Constants for Reactions of Hydrogen Sulfide and the Low-
Molecular-Weight Thiols Cysteine and Glutathione with One- and Two-Electron
Oxidants
Hydrogen Sulfide
(p
K
a
7.0)
Cysteine (p
K
a
8.1-8.4)
glutathione (p
K
a
8.6-9.2)
Two-electron oxidants
Peroxynitrite
4.8 × 10
3
/M/s
4.5 × 10
3
/M/s
1.3 × 10
3
/M/s
(pH 7.4, 37°C) This
work
(pH 7.4, 37°C) [400]
(pH 7.4, 37°C) [267,
268]
Hydrogen
peroxide
0.73/M/s
2.9/M/s
0.87/M/s
(pH 7.4, 37°C) This
work
(pH 7.4, 37°C) [267]
(pH 7.4, 37°C) [267]
Hypochlorite
8 × 10
7
/M/s
3.2 × 10
7
/M/s
≥10
7
/M/s
(pH 7.4, 37°C) This
work
(pH 7.4, 25°C) [399]
(pH 7.4, 25°C) [398]
TauCl
303/M/s
205/M/s
115/M/s
(pH 7.4, 37°C) This
work
(pH 7.4, 24°C) [394]
(pH 7.4, 24°C) [394]
One-electron oxidants
•
NO
2
1.2 × 10
7
/M/s
5.0 × 10
7
/M/s
2.0 × 10
7
/M/s
(pH 7.5, 25°C) This
work
(pH 7.0) [127]
(pH 7.0) [127]
HO
•
1.5 × 10
10
/M/s
3.5 × 10
10
/M/s
2.3 × 10
10
/M/s
(pH 6) [395]
(pH 7.0) [395]
(pH 6.8) [395]
2.0 × 10
8
/M/s
4.6 × 10
7
/M/s
5.3 × 10
6
/M/s
CO
•−
(pH 7.0) [396]
(pH 7.0) [395]
(pH 7.0) [395]
Adapted from Carballal et al. [397] with the permission of Elsevier Inc.
diseases [133]. The significance of the nitration of protein-Tyr and protein-Trp
has been demonstrated. Advancement made in the proteomic and immuno-
logical approaches will help to enhance understanding of the site of modifica-
tion and mechanisms
in vivo
[282]. Kinetics of the reaction between Prx's and
reactive species such as peroxynitrite and peroxides are forthcoming to under-
stand how
M. tuberculosis
can survive even in the presence of reactive oxygen
and nitrogen species. However, mechanisms of these reactions are still far from
being understood, and future work in this field may allow development of new
processes for tuberculosis treatment. Reactive nitrogen species have shown
physiological relevance in enhancing nucleotide exchange in Ras proteins, but
future studies are needed to understand how redox species such as reactive
nitrogen species (e.g.,
•
NO) regulate Ras proteins [404].
Sulfate and phosphate radicals appear to play no significant direct role
in biological systems. However, these radicals are important in atmospheric
and advanced oxidation processes. Sulfate radicals can efficiently oxidize
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