A previously undetected pink copper protein has been isolated from human erythrocytes and purified by chromatographic procedures. The purified protein sedimented as a single symmetrical peak in the ultracentrifuge but minor impurities were detected by polyacrylamide disc electrophoresis. The apparent molecular weight was calculated to be approximately 32,000 by both Bio-Gel P-60 chromatography ...

Superoxide radical (O2.-) is the univalent reduction product of molecular oxygen and belongs to the group of the so-called toxic oxygen derivatives. For years the only enzymatic system known to catalyze the elimination of superoxide was the superoxide dismutase (SOD), which catalyzes dismutation of superoxide radical anions to hydrogen peroxide and molecular oxygen

aerobic and many anaerobic are Table 1. Characteristics of the chloroplastic Cu/Zn-SOD from aspen subiect to oxidative stress resulting from the deleterious efv fects of reduced oxygen species. SOD has been identified as a key enzyme in protecting the cells from oxidative damage by catalyzing the dismutation of superoxide radicals (O2-) to hydrogen peroxide and molecular oxygen (Fridovich, 1986...

Most of the SOD mimics thus far developed belong to the classes of Mn-(MnPs) and Fe porphyrins(FePs), Mn(III) salens, Mn(II) cyclic polyamines and metal salts. Due to their remarkable stability we have predominantly explored Mn porphyrins, aiming initially at mimicking kinetics and thermodynamics of the catalysis of O2(-) dismutation by SOD enzymes. Several MnPs are of potency similar to SOD en...

A eukaryotic cambialistic superoxide dismutase (SOD) has been purified to homogeneity from mature seeds of the disease- and insect-resistant camphor tree (Cinnamomum camphora). Besides the known role of this SOD in protecting cells against oxidative stress, it can induce the cleavage of supercoiled double-stranded DNA into nicked and linear DNA. It can not cleave linear DNA or RNA, demonstratin...

The cytotoxic effects of reactive oxygen species are largely mediated by iron. Hydrogen peroxide reacts with iron to form the extremely reactive and damaging hydroxyl radical via the Fenton reaction. Superoxide anion accelerates this reaction because the dismutation of superoxide leads to increased levels of hydrogen peroxide and because superoxide elevates the intracellular concentration of ir...

Chlorite dismutase (Cld) is a heme b-dependent, O-O bond forming enzyme that transforms toxic chlorite (ClO(2)(-)) into innocuous chloride and molecular oxygen. The mechanism and specificity of the reaction with chlorite and alternate oxidants were investigated. Chlorite is the sole source of dioxygen as determined by oxygen-18 labeling studies. Based on ion chromatography and mass spectrometry...

Reactive oxygen/nitrogen species suppress myocardial oxygen consumption. In this study, we determined that endogenous hydrogen peroxide through dismutation of superoxide enhances postischemic myocardial blood perfusion and oxygen consumption. Electron paramagnetic resonance oximetry was applied to monitor in vivo tissue Po2 in mouse heart subjected to regional ischemia reperfusion. Heart rate, ...