Reactions of Excited States of Phenoxazin-3-one Dyes with Amino Acids¶

It is well known that excited states may be generated chemically in biological systems as evidencex and by the phenomenon of bioluminescence and it is natural to suspect that they may also be generated and used in dark processes (Szent-Györgyi, 1941; Steele, 1963; Cilento, 1965; White & Wei, 1970; Whiteet al.1971). Förster (1967) has pointed out that electronic excitation and subsequent transfer processes may occur in biological dark systems despite the fact that the energy available from enzymic processes is too low to excite aromatic amino acids and other biochemical structures. Hastings (1968) suggests that in some organisms light emission is just an alternative to the formation of an active species.

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Towards an understanding of the molecular mechanism of the unimolecular decomposition of the N-chloro-α-amino acids on the ground and excited states surfaces in aqueous medium

Chemical Physics Letters ◽

10.1016/s0009-2614(97)01288-8 ◽

1998 ◽

Vol 283 (5-6) ◽

pp. 294-300 ◽

Cited By ~ 6

Author(s):

J.J. Queralt ◽

V.S. Safont ◽

V. Moliner ◽

J. Andrés

Keyword(s):

Amino Acids ◽

Aqueous Medium ◽

Molecular Mechanism ◽

Excited States ◽

Unimolecular Decomposition

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Reactions of Excited States of Phenoxazin-3-one Dyes with Amino Acids¶

Photochemistry and Photobiology ◽

10.1562/2004-10-12-ra-342r1.1 ◽

2005 ◽

Vol 81 (4) ◽

pp. 884 ◽

Cited By ~ 9

Author(s):

M. L. Villegas ◽

S. G. Bertolotti ◽

C. M. Previtali ◽

M. V. Encinas

Keyword(s):

Amino Acids ◽

Excited States

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Reactions of excited states of phenoxazin-3-one dyes with amino acids

Photochemistry and Photobiology ◽

10.1562/2004-10-12-ra-342 ◽

2005 ◽

Author(s):

M.L. Villegas ◽

S.G. Bertolotti ◽

C.M. Previtali ◽

Maria V. Encinas

Keyword(s):

Amino Acids ◽

Excited States

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Drug-biomolecule interactions in the excited states

Pure and Applied Chemistry ◽

10.1351/pac200678122277 ◽

2006 ◽

Vol 78 (12) ◽

pp. 2277-2286 ◽

Cited By ~ 9

Author(s):

Virginie Lhiaubet-Vallet ◽

Miguel Angel Miranda

Keyword(s):

Amino Acids ◽

Excited State ◽

Excited States ◽

Binding Sites ◽

Photophysical Properties ◽

Building Blocks ◽

Point Of View ◽

Time Resolved ◽

Specific Antibodies ◽

Chemical Mechanisms

Drug-biomolecule interactions in the excited state are relevant from a photobiological point of view as they can be correlated with a number of photosensitization disorders such as photocarcinogenicity, photoallergy, phototoxicity, etc. Nonsteroidal anti-inflammatory 2-arylpropionic acids and antibacterial fluoroquinolones have been selected as typical examples of photoactive drugs. Protein photosensitization has revealed photoadduct formation; the major amino acids involved are Tyr, Trp, and His. Generation of specific antibodies has allowed us to identify relevant structures of the drug epitopes. Then, drugs have been submitted to systematic steady-state and time-resolved studies on their photophysical properties, alone and in the presence of biomolecules: proteins, DNA, and their simple building blocks. The results are discussed in the framework of the chemical mechanisms underlying photosensitization by drugs and also in connection with the potential of drug excited states as (chiral) reporters for the binding sites of biomolecules.

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