UNIT 7.5 Measurement of MnSOD and CuZnSOD Activity in Mammalian Tissue Homogenates

  1. Douglas R. Spitz,
  2. Larry W. Oberley

Published Online: 1 AUG 2001

DOI: 10.1002/0471140856.tx0705s08

Current Protocols in Toxicology

Current Protocols in Toxicology

How to Cite

Spitz, D. R. and Oberley, L. W. 2001. Measurement of MnSOD and CuZnSOD Activity in Mammalian Tissue Homogenates. Current Protocols in Toxicology. 8:7.5:7.5.1–7.5.11.

Author Information

  1. University of Iowa, Iowa City, Iowa

Publication History

  1. Published Online: 1 AUG 2001
  2. Published Print: MAY 2001


Three basic forms of mammalian SODs exist and they are distinguished by their sizes and locations. SOD enzyme activity is not easily monitored by direct measurement because the substrate disappearance is very rapid at physiological pH. Activity can be measured as described in this unit by a number of indirect competitive inhibition assays based on the principle that the superoxide anion radical will reduce an inhibitory substrate [such as nitroblue tetrazolium (NBT) or cytochrome c] and SOD activity will reduce the rate of reduction in a competitive fashion. The SOD-mediated inhibition of the indicator substrate reduction can then be quantitated and plotted as a function of the quantity of protein added to the reaction to construct an inhibition curve.