On the use of the quenching of luminol luminescence to evaluate SOD activity.
Addition of horseradish peroxidase to a luminol solution (pH = 9.4) produces a burst of light followed by a steady luminescence that lasts for several minutes. This steady-state luminescence is readily quenched by SOD, with a Q1/2 concentration (the additive concentration needed to decrease by one-half the emitted luminescence intensity) of c.a. 4 ng/ml (14 mU/ml). The luminescence intensity decrease can then be employed to evaluate SOD activity in SOD-containing samples. However, the light intensity can also be quenched by additives, such as Trolox, that are able to trap luminol-derived intermediates. It is proposed that double quenching experiments must be performed in order to be able to relate the observed effect of an additive to its SOD-like activity.
Lissi
E
E
Department of Chemistry, Faculty of Science, University of Santiago de Chile.
Pascual
C
C
del Castillo
M D
MD
D000975:Antioxidants; D002839:Chromans; D006735:Horseradish Peroxidase; D007202:Indicators and Reagents; D007700:Kinetics; D008027:Light; D008163:Luminescent Measurements; D008165:Luminol; D011199:Potentiometry / Q000379:methods; D013482:Superoxide Dismutase / Q000032:analysis / Q000378:metabolism*; D013997:Time Factors
D000975:Antioxidants; D002839:Chromans; D007202:Indicators and Reagents; D008165:Luminol; D006735:Horseradish Peroxidase; D013482:Superoxide Dismutase; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid