The tetrazolium dyes MTS and XTT provide new quantitative assays for superoxide and superoxide dismutase

Sutherland, Mark W. and Learmonth, Barbara A. (1997) The tetrazolium dyes MTS and XTT provide new quantitative assays for superoxide and superoxide dismutase. Free Radical Research, 27 (3). pp. 283-289. ISSN 1029-2470


The tetrazolium dyes MTS and XTT were reduced to their soluble formazans by superoxide radical anions (O2_) produced by the oxidation of xanthine by xanthine oxidase under standard conditions. These reactions were compared to the well-known reductions of NBT and cytochrome c by the xanthine/xanthine oxidase system. Reduction of the dyes was completely inhibited by superoxide dismutase (SOD). Rate constants for the reaction of MTS and XTT with O2_: were estimated at 1.3 times .1 times 105 M-1s-1 and 8.6 times .8 times 104 M-1s-1 respectively. The stable MTS and XTT formazans have high extinction coefficients in the visible range which enable sensitive detection and quantification of superoxide radicals, avoiding some of the problems inherent in assays based on production of the insoluble NBT formazan. MTS and XTT have considerable potential both for the quantitative assay of radical production in living tissues and for the assay of superoxide dismutase activity in tissue extracts. Implications for the interpretation of cell culture growth assays which employ these dyes are discussed.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Author's version unavilable in electronic format.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 31 Jul 2008 12:42
Last Modified: 09 Nov 2015 02:10
Uncontrolled Keywords: MTS; NBT; XlT; cytochrome c; superoxide assay; tetrazolium dyes
Fields of Research : 06 Biological Sciences > 0699 Other Biological Sciences > 069999 Biological Sciences not elsewhere classified
06 Biological Sciences > 0601 Biochemistry and Cell Biology > 060106 Cellular Interactions (incl. Adhesion, Matrix, Cell Wall)
03 Chemical Sciences > 0301 Analytical Chemistry > 030104 Immunological and Bioassay Methods
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970106 Expanding Knowledge in the Biological Sciences
Identification Number or DOI: 10.3109/10715769709065766

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