Browsing by Author "LISSI, EA"
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- ItemANTIOXIDANT PROPERTIES OF THE ALKALOID BOLDINE IN SYSTEMS UNDERGOING LIPID-PEROXIDATION AND ENZYME INACTIVATION(1991) SPEISKY, H; CASSELS, BK; LISSI, EA; VIDELA, LABoldine, in low micromolar concentrations, was able to prevent brain homogenate auto-oxidation, the 2,2'-azobis(2-amidinopropane)(AAP)-induced lipid peroxidation of red cell plasma membranes, and the AAP-induced inactivation of lysozyme. These results are indicative of a high reactivity of boldine towards free radicals. The analysis of the boldine effect as a function of incubation times suggests that a metabolite resulting from the interaction of boldine with free radicals also exhibits antioxidant activity, being more efficient than boldine in brain homogenate auto-oxidation and less efficient in lysozyme protection experiments. This behavior may be accounted for in terms of the relative location of the scavengers needed to afford maximal protection.
- ItemPHOTOBEHAVIOR OF PHENYL-CONTAINING METHACRYLATE POLYMERS(1980) ABUIN, EA; LISSI, EA; GARGALLO, L; RADIC, D
- ItemPHOTOBEHAVIOR OF PHENYL-CONTAINING METHACRYLATE POLYMERS .2. DEPENDENCE UPON THE NUMBER OF CHROMOPHORES IN THE STRUCTURAL UNIT(1980) ABUIN, EB; LISSI, EA; GARGALLO, L; RADIC, D
- ItemPHOTOINTERACTION OF BENZOPHENONE TRIPLET WITH LYSOZYME(1989) ENCINAS, MV; LISSI, EA; VASQUEZ, M; OLEA, AF; SILVA, EThe 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.
- ItemSOLVENT DEPENDENT PHOTOPHYSICAL BEHAVIOR OF POLY(1-NAPHTHYL METHACRYLATE)(1979) ABUIN, EA; LISSI, EA; GARGALLO, L; RADIC, D
- ItemTRIPLET BENZOPHENONE DEACTIVATION BY ALPHA-NAPHTHYL METHACRYLATE METHYL-METHACRYLATE COPOLYMERS(1984) ENCINAS, MV; LISSI, EA; GARGALLO, L; RADIC, D; OLEA, AF