Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytochrome c peroxidase oxidises hydrogen peroxide using cytochrome c as the electron donor. This enzyme is found in yeast and bacteria and has been also described in the trematodes Fasciola hepatica and Schistosoma mansoni. Using partially purified cytochrome c peroxidase samples from Fasciola hepatica we evaluated its role as an antioxidant enzyme via the investigation of its ability to protect against oxidative damage to deoxyribose in vitro. A system containing FeIII-EDTA plus ascorbate was used to generate reactive oxygen species superoxide radical, H2O2 as well as the hydroxyl radical. Fasciola hepatica cytochrome c peroxidase effectively protected deoxyribose against oxidative damage in the presence of its substrate cytochrome c. This protection was proportional to the amount of enzyme added and occurred only in the presence of cytochrome c. Due to the low specific activity of the final partially purified sample the effects of ascorbate and calcium chloride on cytochrome c peroxidase were investigated. The activity of the partially purified enzyme was found to increase between 10 and 37% upon reduction with ascorbate. However, incubation of the partially purified enzyme with 1 mM calcium chloride did not have any effect on enzyme activity. Our results showed that Fasciola hepatica CcP can protect deoxyribose from oxidative damage in vitro by blocking the formation of the highly toxic hydroxyl radical (.OH). We suggest that the capacity of CcP to inhibit .OH-formation, by efficiently removing H2O2 from the in vitro oxidative system, may extend the biological role of CcP in response to oxidative stress in Fasciola hepatica.
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PMID:Characterisation of Fasciola hepatica cytochrome c peroxidase as an enzyme with potential antioxidant activity in vitro. 1040 59

Yeast cytochrome c peroxidase (CCP) efficiently catalyzes the reduction of H(2)O(2) to H(2)O by ferrocytochrome c in vitro. The physiological function of CCP, a heme peroxidase that is targeted to the mitochondrial intermembrane space of Saccharomyces cerevisiae, is not known. CCP1-null-mutant cells in the W303-1B genetic background (ccp1Delta) grew as well as wild-type cells with glucose, ethanol, glycerol or lactate as carbon sources but with a shorter initial doubling time. Monitoring growth over 10 days demonstrated that CCP1 does not enhance mitochondrial function in unstressed cells. No role for CCP1 was apparent in cells exposed to heat stress under aerobic or anaerobic conditions. However, the detoxification function of CCP protected respiring mitochondria when cells were challenged with H(2)O(2). Transformation of ccp1Delta with ccp1(W191F), which encodes the CCP(W191F) mutant enzyme lacking CCP activity, significantly increased the sensitivity to H(2)O(2) of exponential-phase fermenting cells. In contrast, stationary-phase (7-day) ccp1Delta-ccp1(W191F) exhibited wild-type tolerance to H(2)O(2), which exceeded that of ccp1Delta. Challenge with H(2)O(2) caused increased CCP, superoxide dismutase and catalase antioxidant enzyme activities (but not glutathione reductase activity) in exponentially growing cells and decreased antioxidant activities in stationary-phase cells. Although unstressed stationary-phase ccp1Delta exhibited the highest catalase and glutathione reductase activities, a greater loss of these antioxidant activities was observed on H(2)O(2) exposure in ccp1Delta than in ccp1Delta-ccp1(W191F) and wild-type cells. The phenotypic differences reported here between the ccp1Delta and ccp1Delta-ccp1(W191F) strains lacking CCP activity provide strong evidence that CCP has separate antioxidant and signaling functions in yeast.
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PMID:Phenotypic analysis of the ccp1Delta and ccp1Delta-ccp1W191F mutant strains of Saccharomyces cerevisiae indicates that cytochrome c peroxidase functions in oxidative-stress signaling. 1701 26