Lysozyme photo-oxidation by singlet oxygen: properties of the partially inactivated enzyme

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dc.contributor.authorSilva, E
dc.contributor.authorDe Landea, C
dc.contributor.authorEdwards, AM
dc.contributor.authorLissi, E
dc.date.accessioned2024-01-10T13:14:32Z
dc.date.available2024-01-10T13:14:32Z
dc.date.issued2000
dc.description.abstractThis work studies the behaviour of partially inactivated lysozyme formed by the effect of singlet oxygen, which was obtained through the irradiation of the native enzyme solution with polychromatic visible light using Methylene Blue as a sensitizer. The polyacrylamide gel analysis of the partially inactivated lysozyme solution shows the presence of different protein fractions. One of them, which corresponds to 53% of the original enzyme, has the same migration as the native enzyme. The others are a mixture of fractions (47%) that show slower migration to the cathode. When this experiment is carried out in the presence of sodium dodecyl sulfate, only one fraction is obtained, which rules out the presence of covalently aggregated forms of lysozyme. The partially inactivated lysozyme has lost 74% of the fluorescence emission of the tryptophan ( Trp) residues. By using the anionic quencher iodide, it is determined that 45 and 36% of the fluorescence emission arising from the native and partially inactivated enzyme, respectively, are due to Trp residues exposed to the solvent. Michaelis-Menten constants (K-m) of 0.296 and 0.511 (mg/ml) and maximum initial rates (V-max) of 0.295 and 0.190 (mg/ml min) are determined for the native and the partially inactivated enzyme solutions, respectively. The same inactivation profile is found when the denaturing effect of increasing urea concentration on both the native and partially inactivated lysozyme is studied. It is postulated that the partially inactivated lysozyme solution is composed of one protein fraction with enzymatic activity similar to that of the native enzyme and also of a mixture of fractions (47% of the total enzyme) with very low activity and characterized by a high tryptophan photo-oxidation. (C) 2000 Elsevier Science S.A. All rights reserved.
dc.fechaingreso.objetodigital2024-04-11
dc.format.extent5 páginas
dc.fuente.origenWOS
dc.identifier.doi10.1016/S1011-1344(00)00049-X
dc.identifier.issn1011-1344
dc.identifier.pubmedidMEDLINE:10942086
dc.identifier.urihttps://doi.org/10.1016/S1011-1344(00)00049-X
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/78416
dc.identifier.wosidWOS:000088198900016
dc.information.autorucActividades Universitarias;Edwards A;S/I;53657
dc.information.autorucQuímica;Silva E;S/I;98771
dc.issue.numero2-3
dc.language.isoen
dc.nota.accesocontenido parcial
dc.pagina.final200
dc.pagina.inicio196
dc.publisherELSEVIER SCIENCE SA
dc.revistaJOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY
dc.rightsacceso restringido
dc.subjectlysozyme
dc.subjectenzyme inactivation
dc.subjectsinglet oxygen
dc.subjectmethylene blue
dc.subjectMichaelis-Menten kinetics
dc.subjectSENSITIZED PHOTOOXIDATION
dc.subjectPEPTIDE-BOND
dc.subjectPROTEINS
dc.subjectREACTIVITY
dc.subjectFLUORESCENCE
dc.subjectDIPEPTIDES
dc.subject.ods03 Good Health and Well-being
dc.subject.odspa03 Salud y bienestar
dc.titleLysozyme photo-oxidation by singlet oxygen: properties of the partially inactivated enzyme
dc.typeartículo
dc.volumen55
sipa.codpersvinculados53657
sipa.codpersvinculados98771
sipa.indexWOS
sipa.indexScopus
sipa.trazabilidadCarga SIPA;09-01-2024
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