Antioxidant reactivity toward nitroxide probes anchored into human serum albumin. A new model for studying antioxidant repairing capacity of protein radicals.
A new strategy to evaluate accessibility of antioxidants to radical proteins has been developed using nitroxide prefluorescent probes anchored into human serum albumin (HSA). Binding association constants for the nitroxide probes C(343)T and QT with HSA were 5 x 10(4) and 9 x 10(4)M(-1), respectively. Rate constants for the nitroxide reduction by antioxidants in HSA were determined finding k(HSA)/k(buffer) ratio of 0.8, 1.9, and 0.075 for ascorbic acid, Trolox, and caffeic acid, respectively, for the nitroxide C(343)T reduction.
Aspée
Alexis
A
Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile.
Orrego
Alejandra
A
Alarcón
Emilio
E
López-Alarcón
Camilo
C
Poblete
Horacio
H
González-Nilo
Danilo
D
D000418:Albumins / Q000502:physiology*; D000693:Anaerobiosis / Q000502:physiology; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism*; D002109:Caffeic Acids / Q000494:pharmacology*; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D012709:Serum Albumin / Q000187:drug effects / Q000378:metabolism*; D013816:Thermodynamics
D000418:Albumins; D000975:Antioxidants; D002109:Caffeic Acids; D012709:Serum Albumin; D009569:Nitric Oxide; D001205:Ascorbic Acid; C040048:caffeic acid