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PHOTO‐INDUCED ELECTRON EJECTION FROM THE REDUCED COPPER OF Pseudomonas aeruginosa AZURIN
Author(s) -
Corin Alan F.,
Gould Ian R.
Publication year - 1989
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.1751-1097.1989.tb04178.x
Subject(s) - azurin , chemistry , photochemistry , copper protein , plastocyanin , copper , electron transfer , solvated electron , absorbance , inorganic chemistry , radical , organic chemistry , radiolysis , chloroplast , gene , biochemistry , photosystem i , chromatography
— The reduced form of Pseudomonas aeruginosa azurin exhibits an enhanced absorbance in the UV compared to that of the oxidized protein. This enhancement has also been observed for azurins from other bacterial species and for another type I copper protein, plastocyanin. Pulsed laser excitation of the reduced azurin in the region of enhanced absorbance at 308 nm results in single photon, rapid (<30 ns) oxidation of the copper center and formation of the hydrated electron with a quantum yield of 0.05. The hydrated electron reacts in the expected manner with scavengers such as nitrous oxide, oxygen, acetone and nitromethane. In the absence of scavengers, the electron reacts with the protein, including the disulfide bond, to form the disulfide radical anion, observed at 410 nm. The overall photophysical event involves a charge‐transfer to solvent transition although the existence of intermediate states can not be excluded.