ؒ
ꢀ
-Radiolysis and the production of OH. γ-Irradiations were
5 C. T. Aravindakumar, J. Ceulemans and M. De Ley, Biochem. J.,
1999, 344, 253.
6 C. T. Aravindakumar, J. Ceulemans and M. De Ley, J. Chem. Soc.,
Perkin Trans. 2, 2002, 663.
60
carried out with a Co-γ-source. The dose rate was determined
27
Ϫ1
by cerric sulfate dosimetry and was about 100 Gy min .
The yields of various radicals and molecular products are
normally expressed as G values which are defined as the number
of molecules formed or destroyed per 100 eV absorption of
radiation energy and in SI units, the yields are: G( OH) ≈
G(eaq ) ≈ G(H O ) = 0.28, G( H) = 0.062, G(H O ) = 0.072 and
G(H ) = 0.047 µmol J . In the presence of N O, G( OH) =
.56 µmol J due to the conversion of eaq into OH according
to eqn. 2, though a variation in this value can be observed
depending on the concentration of the reactive substrate and
7
D. J. Sexton, A. Muruganandam, D. J. McKenney and B. Mutus,
Photochem. Photobiol., 1994, 59, 463.
8 E. J. Langford, A. S. Brown, R. J. Wainwright, A. J. de Belder,
M. R. Thomas, R. E. A. Smith, M. W. Radomski, J. F. Martin and
S. Moncada, Lancet, 1994, 344, 1458.
ؒ
Ϫ
ϩ
ؒ
3
2
2
Ϫ1 28
ؒ
9 A. J. de Belder, C. Lees, J. F. Martin, S. Moncada and S. Campbell,
Lancet, 1995, 345, 124.
2
2
Ϫ1
Ϫ
ؒ
0
1
0 H. R. Swift and D. L. H. Williams, J. Chem. Soc., Perkin Trans. 2,
1
997, 1933.
11 S. C. Askew, D. J. Barnett, J. McAninly and D. L. H. Williams,
29
the reaction rate constant.
J. Chem. Soc., Perkin Trans. 2, 1995, 741.
1
1
1
2 A. P. Munro and D. L. H. Williams, J. Chem. Soc., Perkin Trans. 2,
000, 1794.
3 A. J. Holmes and D. L. H. Williams, J. Chem. Soc., Perkin Trans. 2,
000, 1639.
2
UV/VIS and HPLC analyses. The decay of the RSNOs was
monitored by recording their absorption spectra from 200–
00 nm using a UV/VIS spectrophotometer (Shimadzu
UV160A). The decay as well as the decay products from the
RSNOs were also analysed by HPLC (Shimadzu LC-10 AS)
with a UV/VIS detector (Shimadzu SPD10A). A mixture of
disodium phosphate (1 mM) and sodium sulfate (10 mM) in
water (pH 6) was used as eluent with a flow rate of 1 ml min
for GSNO and with a flow rate of 0.8 ml min for CYSNO and
ACYSNO, using a 25 cm, Nucleosil, 5C-18 column.
2
6
4 M. K. Iwatsuki, M. Yamaguchi and M. Inoue, FEBS Lett., 1996,
389, 149.
15 P. J. Coupe and D. L. H. Williams, J. Chem. Soc., Perkin Trans. 2,
999, 1057.
6 S. Aleryani, E. Milo, Y. Rose and P. Kostka, J. Biol. Chem., 1998,
1
1
1
2
73, 6041.
Ϫ1
7 J. David, T. M. Christie, F. L. Stephen, A. W. David and B. G.
Ϫ1
Matthew, Biochem. Biophys. Res. Commun., 1998, 244, 525.
18 E. Ford, M. N. Hughes and P. Wardman, J. Biol. Chem., 2002, 277,
2
430.
1
2
9 P. J. Thornalley and M. Vasak, Biochim. Biophys. Acta, 1985, 827,
Deoxyribose–TBA assay. This assay has been carried out
30,31
36.
based on a reported procedure.
Equal volumes of irradiated
0 A. B. Ross, W. G. Mallard, W. P. Helman, G. V. Buxton, R. E. Huie
and P. Neta, NDRL-NIST Solution Kinetics Database: ver. 2.0,
National Institute of Standards and Technology, Gaithersburg,
MD, 1994.
sample, which contained 2Ј-deoxy--ribose (DR), and 1% thio-
barbituric acid (TBA) in the presence of 2.8% HCl were heated
on a water bath for 20 min at 100 ЊC. The mixture was then
cooled to room temperature and absorbance at 532 nm was
recorded and the concentration of TBA–Chr was determined
21 J. S. Stamler, Curr. Top. Microbiol. Immunol., 1995, 196, 19.
2
2 V. M. Manoj and C. T. Aravindakumar, Chem. Commun., 2000,
2361.
3
Ϫ1
Ϫ1 30,31
using an absorption coefficient of 153,000 dm mol cm .
An unirradiated solution under the same conditions was used
as a reference and no significant amount of TBA–Chr was
formed in this reference solution. The concentration of DR
2
2
3 T. W. Hart, Tetrahedron Lett., 1985, 26, 2013.
4 S. Oae, Y. H. Kim, D. Fukuhima and K. Shinhama, J. Chem. Soc.,
Perkin Trans. 1, 1978, 913.
25 S. N. Guha, P. N. Moorthy, K. Kishore, D. B. Naik and K. N. Rao,
Ϫ3
Ϫ3
was fixed at 3 × 10 mol dm .
Proc. Indian Acad. Sci. Chem. Sci., 1987, 99, 261.
6 M. S. Panajkar, P. N. Moorthy and N. D. Shirke, BARC Rep., 1988,
2
2
2
2
1
410.
Acknowledgements
7 J. W. Spinks and R. S. Wood, An introduction to Radiation
rd
Chemistry, 3 ed., John Wiley & Sons Inc., New York, 1990.
The authors are thankful to Dr Harimohan (BARC, Mumbai)
for carrying out a few trial pulse radiolysis experiments. We are
also thankful to RRII, Kottayam for providing the gamma
source. VMM is thankful to the CSIR, New Delhi, for a Senior
Research Fellowship. Part of the financial support for this work
is from the Board of Research in Nuclear Sciences (BRNS),
Govt. of India.
8 W. A. Pryor, D. F. Church, C. K. Govindan and G. Gank, J. Org.
Chem., 1982, 47, 156.
9 R. H. Schuler, A. L. Hartzell and B. Behar, J. Phys. Chem., 1981, 85,
192.
30 B. Halliwell and J. M. C. Gutteridge, FEBS Lett., 1987, 128, 347.
3
1 J. M. Joseph, T. L. Luke, U. K. Aravind and C. T. Aravindakumar,
Water Environ. Res., 2001, 73, 243.
2 G. E. Adams, J. W. Boag, J. Currant and B. D. Michael, Pulse
Radiolysis, Academic Press, New York, 1965, 131.
3
3
3
3 J. M. C. Gutteridge, FEBS Lett., 1981, 128, 343.
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O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 1 7 1 – 1 1 7 5
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