Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UNIPROT:P04040 (Catalase)
3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several enzymatic and nonenzymatic reactions play important roles in the physiologic neutralization of hydrogen peroxide (H2O2) in the anterior segment of the eye. The nonenzymatic reactions are particularly important in the aqueous humor, where enzymes are normally absent and high levels of ascorbate are present. One of ascorbate's presumed functions is to protect the lens and retina from the damaging effects of ultraviolet radiation. It also appears to act as an antioxidant for the removal of H2O2. Although H2O2 is frequently a product of antioxidant reactions, the low oxygen tension of the aqueous humor and the absence of trace elements apparently account for the relatively low concentrations of H2O2. This property of aqueous humor is important because high concentrations of H2O2 are toxic to both the lens and the cornea. This damage is exacerbated by the removal of glucose or by inhibition of glutathione reductase--an indication of the importance of the glutathione redox cycle in protecting against endothelial damage induced by H2O2. Catalase also protects the tissues bordering the anterior chamber from H2O2-induced damage. Decreasing catalase activity by treatment with 3-aminotriazole increases the time required for H2O2 clearance from the anterior chamber, thereby allowing more time for H2O2 to produce damage. A decline of catalase activity with age has been observed in the iris and corneal endothelium of rabbits.
...
PMID:Physiologic neutralization mechanisms and the response of the corneal endothelium to hydrogen peroxide. 240 81

Repeated bleomycin administration in animals and humans produces significant lung fibrosis. The pathogenesis of this toxicity may be multifactorial, but it appears to be initiated through the production of radical oxygen species by an activated bleomycin-iron-oxygen ternary complex. Protection of lung tissue from bleomycin-induced toxicity may occur through both specific metabolic inactivation of bleomycin by the enzyme bleomycin hydrolase, as well as by such non-specific antioxidants as catalase and the glutathione system. The effect of chronic, systemic administration of bleomycin on the activities and levels of these enzymes and proteins in pulmonary tissue is unknown. C57BL/6 mice were injected subcutaneously with saline, non-fibrogenic (2 mg/kg) and fibrogenic (10 mg/kg) doses of bleomycin twice-weekly for 6 weeks. Animals were killed at 0, 1.5, 3, and 6 weeks after initiation of bleomycin treatment. Catalase activity was increased more than 50% at 3 weeks in the low-dose animals, and was decreased over 40% at 6 weeks in the high-dose animals. Total lung glutathione levels were unaffected in both groups, although glutathione reductase activity was increased significantly (over 2-fold) at 1.5 and 3 weeks in the high-dose animals. At 6 weeks glutathione reductase was increased 7- and 12-fold in low and high-dose animals respectively. Glutathione peroxidase activity also was elevated more than 2-fold above control values at 6 weeks in both sets of animals. There was no evidence of induction of bleomycin hydrolase activity at any time point. Rather, bleomycin hydrolase activity was decreased significantly to 30 and 40% of control values at 3 and 6 weeks, respectively, in mice receiving the fibrogenic doses of bleomycin. These results demonstrate that chronic, systemic administration of non-fibrogenic and fibrogenic doses of bleomycin produces changes in activity of lung antioxidant defense mechanisms. The early loss of lung bleomycin hydrolase activity may contribute to the pathogenesis of bleomycin-induced pulmonary toxicity following repeated drug exposure.
...
PMID:Alterations in pulmonary protective enzymes following systemic bleomycin treatment in mice. 245 25

We have previously reported that rat pulmonary alveolar epithelial cells are resistant to neutrophil-generated oxidants in contrast to the situation described for endothelial cells. In the present study, we investigated the roles of intracellular catalase and glutathione-dependent reactions in providing protection against cytotoxic concentrations of H2O2 and stimulated neutrophils. Catalase was found to be instrumental in protecting epithelial cells because when inhibited by either azide or 3-amino-1,2,4-triazole, there was an increase in the cytotoxic effect of exogenous H2O2 and stimulated neutrophils. Associated with this potentiation of injury was a reduction in epithelial cell clearance of H2O2. Partial inhibition of glutathione-dependent reactions by depleting intracellular glutathione with buthionine sulfoximine or by inhibiting the enzyme glutathione reductase with 1,3-bis(2-chloroethyl)-1-nitrosourea also augmented the cytotoxic effect of both H2O2 and stimulated neutrophils. This increase in neutrophil-induced cytotoxicity was caused by the addition of an oxidant-dependent mechanism of killing on top of the previously described oxidant-independent pathway. Importantly, the increased susceptibility to injury caused by inhibition of glutathione-dependent reactions was not associated with a reduction in epithelial cell consumption of exogenous H2O2, contrary to the case with catalase. This suggests that there are glutathione-dependent reactions that protect epithelial cells in ways separate from reducing the total burden of exogenous H2O2 on the cells.
...
PMID:Resistance of rat pulmonary alveolar epithelial cells to neutrophil- and oxidant-induced injury. 262 61

The cytosolic status during aging of several antioxidants and enzymatic activities which protect the cell from oxidative damage was explored in the liver of ad libitum-fed and food restricted rats. Restricting calories effectively prevented the age-related decrease in cellular glutathione that occurs in ad libitum-fed rats. Although glutathione reductase exhibited little change with age in ad libitum-fed rats, dietary restriction resulted in greater activity of this enzyme than that of ad libitum-fed animals. Glutathione S-transferase activity of ad libitum-fed rats decreased significantly with age in ad libitum-fed rats but not in food restricted rats. The glutathione peroxidase activity which increased until 12 months in the ad libitum-fed rats declined by 24 months; there was little change with adult age in this enzymatic activity in food restricted rats. Catalase activity declined steadily from 3-24 months in the ad libitum-fed rats, and food restriction prevented this age-related decline. The significance of antioxidants and the related protective enzymes is discussed relative to membrane alterations and the anti-oxidative action of food restriction in relation to age-related degenerative damages.
...
PMID:Effect of chronic food restriction in aging rats. II. Liver cytosolic antioxidants and related enzymes. 273 62

The activities of superoxide dismutase (SOD), glutathione peroxidase, glutathione reductase, and catalase were measured in isolated brain capillaries, choroid plexus, cerebrum, and cerebellum from rats of 2, 6, 12, and 24 months. The contents of copper, zinc, and manganese were determined in capillaries, cerebrum, and cerebellum, and the profile of fatty acids was studied in brain capillaries. In brain capillaries, the activities of glutathione peroxidase and glutathione reductase did not change with age. The activities of the two enzymes increased in cerebrum and cerebellum. In choroid plexus, glutathione peroxidase activity increased, but glutathione reductase activity remained unchanged. Catalase activity in brain capillaries declined, whereas in choroid plexus, cerebrum, and cerebellum, it did not change. The activities of the three enzymes were significantly higher in brain capillaries and choroid plexus than in cerebrum and cerebellum. SOD activity increased in the four tissues. Copper content in the capillaries increased initially and then levelled off, whereas it continued to increase in cerebrum and cerebellum. Zinc increased in brain capillaries, but did not vary in cerebrum and cerebellum. Manganese content remained constant in all tissues studied. The percent of saturated fatty acids in brain capillaries did not change with age, whereas those of mono- and polyunsaturated fatty acids increased and decreased, respectively. The possibility that a deficiency of enzymes protective against free radicals causes blood-brain barrier and blood-cerebrospinal fluid barrier degeneration is ruled out.
...
PMID:Antioxidant enzymes and related trace elements in aging brain capillaries and choroid plexus. 276 Jun 21

Relative resistance to oxygen toxicity in newborn animals (compared to adults) has been associated with increased antioxidant enzymes and glutathione in lung homogenate. The cell type(s) involved in this increase is unknown. We investigated the effect of hyperoxia in vitro and in vivo on the following antioxidants (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, and glutathione) in alveolar type II cells from neonatal rats. Type II cells were exposed to 95% oxygen or air for 48 h in vitro. When expressed per microgram DNA, all the antioxidants except catalase increased during in vitro incubation; only glucose-6-phosphate dehydrogenase and glutathione increased when expressed per mg protein. None of the antioxidants was higher in oxygen-exposed cells than in air-exposed cells. Neonatal rats were exposed to 100% oxygen or air in vivo for 4 d before determination of antioxidants in lung homogenate supernatant and alveolar type II cells. Catalase, glutathione peroxidase, and glutathione reductase were higher but glucose-6-phosphate dehydrogenase and glutathione were lower in type II cells than in lung homogenate from control animals. Alveolar type II cell glucose-6-phosphate dehydrogenase and glutathione were increased but catalase and glutathione reductase were decreased by exposure to hyperoxia. We conclude that the oxygen-induced increase in whole lung antioxidants is not explained by alveolar type II cell hypertrophy or increased antioxidants within type II cells during hyperoxia.
...
PMID:Effect of hyperoxia on antioxidants in neonatal rat type II cells in vitro and in vivo. 281 89

The enzymes involved in antioxidative activity and the cellular content of the antioxidants glutathione and ascorbate in the cyanobacteria Nostoc muscorum 7119 and Synechococcus 6311 have been examined for their roles in hydroperoxide removal. High activities of ascorbate peroxidase and catalase were found in vegetative cells of both species and in the heterocysts of N. muscorum. The affinity of ascorbate peroxidase for H2O2 was 15- to 25-fold higher than that of catalase. Increased activity of ascorbate peroxidase was observed in N. muscorum when H2O2 production was enhanced by photorespiration. Catalase activity was decreased in dilute cultures whereas ascorbate peroxidase activity increased. Ascorbate peroxidase activity also increased when the CO2 concentration was reduced. Ascorbate peroxidase appears to be a key enzyme in a cascade of reactions regenerating antioxidants. Dehydroascorbate reductase was found to regenerate ascorbate, and glutathione reductase recycled glutathione. In vegetative cells glutathione was present in high amounts (2-4 mM) whereas the ascorbate content was almost 100-fold lower (20-100 microM). Glutathione peroxidase was not detected in either cyanobacterium. It is concluded from the high activity of ascorbate peroxidase activity and the levels of antioxidants found that this enzyme can effectively remove low concentrations of peroxides. Catalase may remove H2O2 produced under photooxidative conditions where the peroxide concentration is higher.
...
PMID:Hydroperoxide metabolism in cyanobacteria. 308 78

This study examined the effects of gossypol acetic acid on the antioxidant defense system of the rat testis. In gossypol-treated animals testis catalase and glutathione peroxidase activities were decreased. Catalase and glutathione peroxidase are the two enzymes that protect against oxidative damage by hydrogen peroxide. Other antioxidants that were reduced in treated animals were glucose-6-phosphate dehydrogenase, superoxide dismutase, glutathione reductase, alpha-tocopherol, and ascorbate. Gossypol, a pigment of cottonseed and cottonseed products, causes infertility in humans and many animal species, but its mechanism of action is unknown. Gossypol is known to produce reactive oxygen species in vitro. Oxidative injury caused by the generation of reactive oxygen species and a compromised antioxidant defense system may be responsible for the antifertility effects of gossypol.
...
PMID:Effects of gossypol on the antioxidant defense system of the rat testis. 319 Mar 61

Xanthine (X) and xanthine oxidase (XO) were injected intratracheally (IT) in hamsters at Day 0 (38 mg X, 100 micrograms XO) and Day 5 (38 mg X, 250 micrograms XO). Control hamsters received saline or X (38 mg) plus boiled XO (100, 250 micrograms). Cytoplasmic superoxide dismutase (SOD) activity increased from control of 286 to 337 and 335 units/lung at Days 12 and 19, respectively, but decreased to 228 units/lung at Day 33; mitochondrial SOD activity increased at Day 12 from control of 57 to 71 units/lung and then decreased at Days 26 and 33 to 42 and 33 units/lung, respectively. Glutathione peroxidase (GP) and glutathione reductase (GR) activities rose from their control values of 1161 and 1151 to 1561 and 2287 units/lung at Day 12, respectively; thereafter, GR activity decreased to 512 and 462 units/lung at Days 19 and 26, respectively. Glutathione transferase declined at Day 12 but increased at Day 26 after initial treatment. Glucose-6-phosphate dehydrogenase activity declined from control of 1071 to 693 units/lung at Day 2 and returned to control thereafter. Catalase activity remained unaffected. Hydroxyproline was increased from 903 micrograms/lung in control to 1080, 1301, 1195, and 1148 micrograms/lung at Days 12, 19, 26, and 33, respectively. Malonaldehyde increased from 40 nmole/lung in control to 70 and 113 nmole/lung at Days 12 and 33, respectively. The ratio of right ventricle to left ventricle and septum increased significantly from control of 0.277 to 0.318 at Day 33. Histopathology at Days 2 and 4 revealed peribronchiolar and arteriolar inflammation, and diffuse alveolitis. By Day 12 there were thickened alveolar septa and foci of fibrotic consolidation.
...
PMID:Effects of intratracheal administration of xanthine plus xanthine oxidase on lung antioxidant enzymes, lipid peroxidation, and collagen in hamsters. 319 17

In the mid-fifth instar larvae of the cabbage looper moth, Trichoplusia ni, the subcellular distribution of total superoxide dismutase was as follows: 3.05 units (70.0%), 0.97 units (22.3%), and 0.33 units (7.6%) mg-1 protein in the mitochondrial, cytosolic and nuclear fractions, respectively. No superoxide dismutase activity was detected in the microsomal fraction. Catalase activity was unusually high and as follows: 283.4 units (47.3%), 150.1 units (25.1%), 142.3 units (23.8%), and 22.9 units (3.8%) mg-1 protein in the mitochondrial, cytosolic, microsomal (containing peroxisomes), and nuclear fractions. No glutathione peroxidase activity was found, but appreciable glutathione reductase activity was detected with broad subcellular distribution as follows: 3.86 units (36.1%), 3.68 units (34.0%), 2.46 units (23.0%), and 0.70 units (6.5%) mg-1 protein in the nuclear, mitochondrial, and cytosolic fractions, respectively. The unusually wide intracellular distribution of catalase in this phytophagous insect is apparently an evolutionary adaptation to the absence of glutathione peroxidase; hence, lack of a glutathione peroxidase-glutathione reductase role in alleviating stress from lipid peroxidation. Catalase working sequentially to superoxide dismutase, may nearly completely prevent the formation of the lipid peroxidizing .OH radical from all intracellular compartments by the destruction of H2O2 which together with O2- is a precursor of .OH.
...
PMID:Antioxidant enzymes of larvae of the cabbage looper moth, Trichoplusia ni: subcellular distribution and activities of superoxide dismutase, catalase and glutathione reductase. 324 4


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---