Abstract
Superoxide dismutases (SODs) act as a primary defence against reactive oxygen species (ROS) by converting superoxide anion radicals (O2 -) into molecular oxygen (O2) and hydrogen peroxide (H2O2). Members of this enzyme family include CuZnSODs, MnSODs, FeSODs, and NiSODs, depending on the nature of the cofactor that is required for proper activity. Most eukaryotes, including yeast, possess CuZnSOD and MnSOD. This protocol aims at assessing the activity of the yeast Saccharomyces cerevisiae MnSOD Sod2p from cellular extracts using nitroblue tetrazolium staining. This method can be used to estimate the cellular bioavailability of Mn2+ as well as to evaluate the redox state of the cell.