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FLASH PHOTOLYSIS OF 3‐IODOTYROSINE IN AQUEOUS SOLUTION AT pH 5
Author(s) -
Arvis M.,
Kraljić I.,
Girma J. P.,
Morgat J. L.
Publication year - 1978
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.1751-1097.1978.tb07693.x
Subject(s) - chemistry , flash photolysis , radical , aqueous solution , reaction rate constant , kinetics , dimer , photodissociation , photochemistry , iodine , ethanol , absorption (acoustics) , yield (engineering) , hydrogen atom abstraction , absorption spectroscopy , organic chemistry , physics , materials science , quantum mechanics , acoustics , metallurgy
— The 3‐tyrosinyl free radicals (3‐Tyr) and iodine atom are formed by flash photolysis of 3‐iodotyrosine (3‐Tyr‐I) in aqueous solutions at pH 5. The presence of iodine atoms in the medium is characterized by the absorption spectrum and the decay kinetics of I formed when KI is added to the system. In the absence of radical scavengers, the 3‐Tyr adds to or reacts with the parent molecule to produce a transient species, probably a radical dimer, which has an absorption maximum at 405 nm. The decay of this transient follows second order kinetics whose rate constant increases with decreasing 3‐iodotyrosine concentration. Measurements of the dependence of the transient yield on the concentration of added ethanol indicate that the 3‐Tyr radical reacts with ethanol by hydrogen abstraction. The rate constants of reaction of the 3‐Tyr radical with 3‐iodotyrosine and ethanol are deduced from results.