Browsing by Author "OLEA, AF"

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    PHOTOINTERACTION OF BENZOPHENONE TRIPLET WITH LYSOZYME
    (1989) ENCINAS, MV; LISSI, EA; VASQUEZ, M; OLEA, AF; SILVA, E
    The quenching of the benzophenone triplet by lysozyme and its constituent amino acids in aqueous solutions have been studied. Native lysozyme quenches the benzophenone triplet with a high rate constant, 4 .times. 109 M-1s-1. The quenching process takes place with production of significant amounts of free ketyl radicals, .PHI.ketyl = 0.56, but with a very low benzophenone consumption yield (0.022). The consumption yield is considerably smaller than that observed for the free amino acids. This difference can be explained in terms of a dominant back hydrogen transfer to the protein in the disproportionation of the free radicals produced. Reduced and carboxymethylated lysozyme shows a higher quenching rate (7.8 .times. 109 M-1s-1) and a larger benzophenone consumption yield (0.07). The deactivation of the benzophenone triplet by the native protein leads to its inactivation, with a quantum yield of 0.01. Tryptophan and arginine residues are destroyed with a quantum yield of 0.01. In the modified enzyme tryosine and methionine groups are also consumed.
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    TRIPLET BENZOPHENONE DEACTIVATION BY ALPHA-NAPHTHYL METHACRYLATE METHYL-METHACRYLATE COPOLYMERS
    (1984) ENCINAS, MV; LISSI, EA; GARGALLO, L; RADIC, D; OLEA, AF