copper-containing forms of the copper -zinc dismu-N,N-Diethyldithiocarbamate has been shown to be tase obtained from red cell extracts from which hemoan analytical stain for copper in native polyacrylamide globin has been removed (1). This reagent reacts with gels of the copper-zinc superoxide dismutase from pucopper in the gels to form stable yellow -brown bands rified preparations as well as from crude red cell exthat are quantifiable at 448 nm. Any color in gels tracts, i.e., lysates from which hemoglobin has been due to trace hemoglobin or hemoglobin degradation removed (Jewett, S. L., and Rocklin, A. M. (1994) Anal. products from the red cells is bleached overnight dur-Biochem. 217, 236-240). Applying this methodology, it ing staining with the dithiocarbamate. This staining was found that the relative amounts of copper-conmethod has been applied in this study to the examitaining forms of copper-zinc superoxide dismutase nation of the distribution of copper forms of superox-(EC 1.15.1.1) from bovine red cell extracts did not ide dismutase from young and old red cells and from change significantly with either the age or with hydroperoxide-treated red cells. These two types of studies gen peroxide treatment of the red cells. Furthermore, were chosen for applications of the staining methodno significant changes were seen in the specific activology because small losses of superoxide dismutase ity of the dismutase in either type of experiment. These activity have been reported by Bartkowiak et al. (2) observations for both types of experiments are conand Bartoz et al. (3) for older red cells and much trary to what was expected from similar studies relarger losses of dismutase activity were reported by ported in the literature. However, discrepancies may Salo et al. (4) in red cells treated with peroxide. It 1 This work was supported by NIH AREA Grant 1R15DK4146a corresponding increase in two faster-moving bands 001A2, the Student Projects Committee (to A.M.R.), and the Research and Grants Committee, California State University, Founda-( 6). Using bathocuproine disulfonate to detect copper tion, Northridge. We acknowledge the help of Jonas Masikat, Helen released from the dismutase in solution and dithiocar-