Photochemistry and Photobiology, 2002, 76(1) 45
knowledges the receipt of an Australian Postgraduate Award admin-
istered through the University of Sydney.
REFERENCES
1
. Kanofsky, J. R. (1983) Singlet oxygen production by lactoper-
oxidase. J. Biol. Chem. 258, 5991–5993.
2
. Kanofsky, J. R., J. Wright, G. E. Miles-Richardson and A. I.
Tauber (1984) Biochemical requirements for singlet oxygen
production by purified human myeloperoxidase. J. Clin. Inves-
tig. 74, 1489–1495.
3
4
5
. Kanofsky, J. R. and B. Axelrod (1986) Singlet oxygen produc-
tion by soybean lipoxygenase isozymes. J. Biol. Chem. 261,
1
099–1104.
. Kanofsky, J. R., H. Hoogland, R. Wever and S. J. Weiss (1988)
Singlet oxygen production by human eosinophils. J. Biol. Chem.
2
0, 9692–9696.
. Steinbeck, M. J., A. U. Khan and M. J. Karnovsky (1992) In-
tracellular singlet oxygen generation by phagocytosing neutro-
phils in response to particles coated with a chemical trap. J.
Biol. Chem. 267, 13425–13433.
6
7
. Steinbeck, M. J., A. U. Khan and M. J. Karnovsky (1993) Ex-
tracellular production of singlet oxygen by stimulated macro-
phages quantified using 9,10-diphenylanthracene and perylene
in a polystyrene film. J. Biol. Chem. 268, 15649–15854.
. Bensasson, R. V., E. J. Land and T. G. Truscott (1993) Excited
States and Free Radicals in Biology and Medicine. Oxford Uni-
versity Press, Oxford.
Scheme 2.
8
. Plesnicar, B. (1992) Polyoxides. In Organic Peroxides, (Edited
by W. Ando), pp. 479–533. John Wiley and Sons, Chichester.
. Straight, R. C. and J. D. Spikes (1985) Photosensitized oxidation
ty acid hydroperoxides (45). The detection of significant
spectral changes for both radical adducts on use of the 3,5-
9
of biomolecules. In Singlet O , Vol. 4 (Edited by A. A. Frimer),
2
ring-d Tyr is consistent with both species being centered at
the 3 (or 5) position. However, the additional differences
between the adducts detected from 3,5-ring-d2 Tyr and
pp. 91–143. CRC Press, Boca Raton.
0. Tyrrell, R. M. (2000) Role for singlet oxygen in biological ef-
2
1
fects of ultraviolet A radiation. Methods Enzymol. 319, 290–
2
96.
2
,3,5,6-ring-d Tyr suggest that the second radical species—
4
11. Giacomoni, P. U. (Editor)(2001) Sun Protection in Man. Elsev-
that which has two proton couplings—is a C –C –centered
ier, Amsterdam.
3
5
1
1
1
1
2. Davies, M. J. and R. J. W. Truscott (2001) Photo-oxidation of
proteins and its consequences. In Sun Protection in Man, (Ed-
ited by P. U. Giacomoni), pp. 251–275. Elsevier, Amsterdam.
3. Matheson, I. B. C., R. D. Etheridge, N. R. Kratowich and J. Lee
(1975) The quenching of singlet oxygen by amino acids and
proteins. Photochem. Photobiol. 21, 165–171.
radical, with the second smaller coupling arising from C (or
2
C ). This second species is assigned to a radical adduct de-
6
rived from the initial epoxide as a result of hydrolytic ring
opening (i.e. reaction C, Scheme 2).
In conclusion, it has been demonstrated that O -mediated
1
2
4. Michaeli, A. and J. Feitelson (1994) Reactivity of singlet oxy-
gen toward amino acids and peptides. Photochem. Photobiol.
oxidation of free Tyr gives rise to multiple intermediate per-
oxides including two isomers of (2), presumably via the in-
termediacy of (1), and that these species undergo thermal
decay to give two isomers of the ring-closed indolic alcohol
HOHICA. These species have been characterized in detail.
In contrast, N-protected tyrosine derivatives, and Tyr resi-
dues in peptides, give rise to long-lived, ring-derived hydro-
5
9, 284–289.
5. Wilkinson, F., W. P. Helman and A. B. Ross (1995) Rate con-
stants for the decay and reactions of the lowest electronically
excited state of molecular oxygen in solution. An expanded and
revised compilation. J. Phys. Chem. Ref. Data 24, 663–1021.
6. Papeschi, G., M. Monici and S. Pinzauti (1982) pH effect on
dye sensitized photooxidation of aminoacids and albumins.
Med. Biol. Environ. 10, 245–250.
1
peroxides with the peroxide function present at the C ring
1
position. These materials have been fully characterized by
17. Endo, K., K. Seya and H. Hikino (1988) Photo-oxidation of L-
1
tyrosine, an efficient, 1,4-chirality transfer reaction. J. Chem.
Soc. Chem. Commun. 934–935.
NMR and are the likely O -mediated oxidation products of
2
Tyr residues on proteins. At low temperatures these hydro-
peroxides decay to the corresponding alcohols, which may
1
8. Jin, F. M., J. Leitich and C. von Sonntag (1995) The photolysis
( ϭ 254 nm) of tyrosine in aqueous solutions in the absence
1
be suitable markers of O -mediated oxidation of Tyr resi-
and presence of oxygen—the reaction of tyrosine with singlet
oxygen. J. Photochem. Photobiol. A Chem. 92, 147–153.
2
dues on proteins. At physiological temperatures, and partic-
ularly in the presence of UV light or metal ions, these hy-
droperoxides can give rise to further reactive radicals. Both
the parent hydroperoxides, and radicals derived from them,
may mediate further oxidative damage. Initial studies (23)
have shown that these species can inhibit key cellular en-
1
9. Criado, S., A. T. Soltermann, J. M. Marioli and N. A. Garcia
(1998) Sensitized photooxidation of di- and tripeptides of ty-
rosine. Photochem. Photobiol. 68, 453–458.
20. Roberts, J. E. (2001) Hazards of sunlight exposure in the eye.
In Sun Protection in Man, (Edited by P. U. Giacomoni), pp.
1
55–174. Elsevier, Amsterdam.
2
1. Sysak, P. K., C. S. Foote and T.-Y. Ching (1977) Chemistry of
singlet oxygen—XXV. Photooxygenation of methionine. Pho-
tochem. Photobiol. 26, 19–27.
1
zymes. The formation and subsequent reactions of O -me-
2
diated protein peroxides may therefore play a key role in the
1
damage induced by UV light and other sources of O .
22. Straight, R. C. and J. D. Spikes (1978) Sensitized photooxygen-
ation of amino acids: effects on the reactvity of their primary
amine groups with fluorescamine and O-phthalaldehyde. Pho-
tochem. Photobiol. 27, 565–569.
2
Acknowledgments The authors thank the Australian Research
Council and the Wellcome Trust for financial support. A.W. ac-