Premium
THE PHOTOCHEMICAL INTERACTION BETWEEN THE TRIPLET STATE OF 8‐METHOXYPSORALEN AND THE MELANIN PRECURSORL–3, 4 DIHYDROXYPHENYLALANINE
Author(s) -
CRAW M.,
CHEDEKEL M. R.,
TRUSCOTT T. G.,
LAND E. J.
Publication year - 1984
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1984.tb03422.x
Subject(s) - flash photolysis , chemistry , radiolysis , dihydroxyphenylalanine , melanin , photochemistry , triplet state , excited state , photodissociation , solvated electron , kinetics , organic chemistry , molecule , aqueous solution , biochemistry , physics , quantum mechanics , neuroscience , nuclear physics , reaction rate constant , biology , dopamine
— The photochemical interaction between 8‐methoxypsoralen (8‐MOP) and the melanin precursorL–3,4‐dihydroxyphenylalanine(dopaH 2 ) has been studied using laser flash photolysis. Triplet excited 8‐MOP was thus found to abstract electrons from dopaH 2 ( k ∼ 2 × 10 9 dm 3 mol ‐1 s ‐1 ) to form semireduced 8‐MOP and semioxidised dopaH 2 .The technique of pulse radiolysis was used to establish separately the spectra of (a) the semi‐reduced form of 8‐MOP at pH 6.5 and (b) the semioxidised forms of dopaH 2 at pH 6.5, 5.8, 4.6 and 3.3. The corresponding λ max and extinction coefficients found were: for 8‐MOP at pH 6.5, λ max = 350 nm (= 9050 dm 3 mol ‐1 cm ‐1 ); for dopa at pH 6.5, λ max = 305 nm (ε= 12000 dm 3 mol ‐1 cm ‐1 ) and for dopaH at pH 3.3, λ= 305 nm (ε= 5900 dm 3 mol ‐1 cm ‐1 ).