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Catalase from acatalasemic dog liver was purified to homogeneity and its properties were compared with those of normal dog liver catalase. The purified acatalasemic and normal dog liver catalases were found to have the same molecular weight (230,000 Da) and isoelectric point (pI: 6.0-6.2) and both enzymes contained four hematins per molecule. The catalytic activity of catalase from acatalasemic dog was normal. Furthermore, there was no difference between the acatalasemic and normal dog catalases in the binding affinity to NADPH (apparent Kd: 0.11-0.12 microM) and in the sensitivity to oxidative stress by hydrogen peroxide, the normal substrate of catalase. The acatalasemic dog enzyme was stable only in a narrow pH range (pH 6-9) although the normal enzyme was stable in a wide pH range (pH 4-10). Acatalasemic dog liver catalase also showed a slight low thermal stability at 37 degrees C and the heat-lability was remarkable at 45 degrees C, compared to the normal dog enzyme. These results indicated that the acatalasemic dog catalase is catalytically normal although it is associated with an unstable molecular structure.  相似文献   

4.
Monomeric, dimeric and tetrameric forms of mouse liver catalase have been shown to express peroxidatic activity while the tetrameric form expresses the catalic activity. Autosomally inherited acatalasemia, produced by X-ray irradiation of mice results in almost complete loss of catalic activity of catalase but has no effect on the peroxidatic activity. Liver catalase from normal and acatalasemic mice was purified by following the catalic and peroxidatic activity, respectively. Antiserum produced in rabbit against catalase from normal mouse completely precipitated the catalatic and peroxidatic activity from normal liver, and peroxidatic activity from the acatalasemic liver homogenate. Similar results were obtained when antiserum against peroxidase from acatalasemic mice was used. These studies indicate that acatalasemia in mice is due to a structural gene mutation which leads to synthesis of structurally altered catalase subunits. The altered subunits express peroxidatic activity but do not combine to form a tetramer which expresses catalatic activity.  相似文献   

5.
Summary Liver cell lines with very low catalase activity were established from an acatalasemic mouse. Hepatocytes isolated by a collagenase-liver-perfusion technique were cultured in Williams’ E medium supplemented with 10% fetal bovine serum. The acatalasemic liver cell line showed approximately 20% of the catalase activity of a normal mouse liver cell line, whereas its glutathione peroxidase activity was approximately equal to that of the normal liver cell line. DNA sequence analysis of this cell line showed the same mutation in the catalase gene as is seen in the acatalasemic mouse. Our observation of intracellular content of hydrogen peroxide (H2O2) radical and increased susceptibility of the cells to H2O2 were compatible with the existence of low catalase activity in the acatalasemic mouse. This hepatocyte cell line should be useful for studying effects of oxidative radical stress at the cellular level.  相似文献   

6.
The enzyme catalase protects aerobic organisms from oxygen-free radical damage by converting hydrogen peroxide to molecular oxygen and water before it can decompose to form the highly reactive hydroxyl radical. Hydroxyl radicals are the most deleterious of the activated oxygen intermediates found in aerobic organisms. If formed, they can react with biological molecules in their proximity; the ensuing damage has been implicated in the increasing risk of disease and death associated with aging. To study further the regulation and role of catalase we have undertaken a molecular characterization of the Drosophila catalase gene and two potentially acatalasemic alleles. We have demonstrated that a previously existing allele, Cat(n4), likely contains a null mutation, a mutation which blocks normal translation of the encoded mRNA. The Cat(n1) mutation appears to cause a significant change in the protein sequence; however, it is unclear why this change leads to a nonfunctioning protein. Viability of these acatalasemic flies can be restored by transformation with the wild-type catalase gene; hence, we conclude that the lethality of these genotypes is due solely to the lack of catalase. The availability of flies with transformed catalase genes has allowed us to address the effect of catalase levels on aging in Drosophila. Though lack of catalase activity caused decreased viability and life span, increasing catalase activity above wild-type levels had no effect on normal life span.  相似文献   

7.
Historically, it has been theorized that the oxidant sensitivity of glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes arises as a direct consequence of an inability to maintain cellular gluthione (GSH) levels. This study alternatively hypothesizes that decreased NADPH concentration leads to impaired to catalase activity which, in turn, underlies the observed oxidant susceptibility. To investigate this hypothesis, normal and G6PD-deficient erythrocytes and hemolysates were challenged with a H2O2-generating agent. The results of this study demonstrated that catalase activity was severely impaired upon H2O2 challenge in the G6PD-deficient cell whiel only decrease was observed in normal cells. Supplmentation of either normal or G6PD-deficient hemolysates with purified NADPH was found to significantly (P < 0.001) inhibit catalase inactivation upon oxidant challenge while addition of NADP+ had no effect. Analysis of these results demonstrated direct correlation between NADPH concentration and catalase activity (r = 0.881) and an inverse correlation between catalase activity and erythrocyte oxidant sensitivity (r = 0.906). In contrast, no correlation was found to exist between glutathione concentration (r = 0.170) and oxidant sensitivity. Analysis of NADPH/NADPt ration in acatalasemic mouse erythrocytes demonstrated that NADPH maintenance alone was not sufficient to explain oxidant resistance, and that catalase activity was required. This study supports the hypothesis that impaired catalase activity underlies the enhanced oxidant sensitivity of G6PD-deficient erythrocytes and elucidates the importance of NADPH in the maintenance of normal catalase activity.  相似文献   

8.
Catalase in hemolysates of normal, heterozygous hypocatalasemic and acatalasemic Japanese was immunotitrated with an anti-human blood catalase rabbit serum. Equivalence points were calculated from the regression lines between catalase activity added and catalase activity remaining in the supernatant. Catalase activities at the equivalence points of Japanese normal, hypocatalasemia and acatalasemia were similar. The results indicate that the specific activities of catalase in the normal and of the variant bloods are identical. Catalase in hemolysates of normal and variant mice was immunotitrated with an anti-mouse liver catalase rabbit serum. In contrast to Japanese acatalasemic subject, the equivalence points of catalase in heterozygous hypocatalasemic, homozygous hypocatalasemic, acatalasemic and normal hemolysates were different, and the ratios of specific activity in these variant mice to that in normal were 0.72, 0.46 and 0.21, respectively. The differences in catalase activities at equivalence points were also supported by the statistical analysis on parameters of regression lines of catalase activities remaining in the supernatant on catalase activities added in the immunotitration. These findings suggest that the molecular properties of residual catalase of Japanese acatalasemia and those of mouse acatalasemia are entirely different.  相似文献   

9.
The unstable catalase variant found in the blood of individuals homozygous for Swiss-type acatalasemia and the enzyme species present in heterozygous carriers of this rare defect have been further characterized. The mutant enzyme isolated from acatalasemic red cells is considerably more heat labile and differs in electrophoretic mobility from the normal enzyme. Catalase preparations obtained from heterozygotes consist of an apparently uniform enzyme species, probably representing a molecular hybrid, with properties intermediate to those of the normal and the variant enzyme. However, antigenic identity of catalase from all three sources is observed. Model experiments indicate that hybrid catalase molecules can be produced by recombining normal and variant dimer subunits. Fractionation of erythrocytes according to density and age shows that most of the residual catalase activity is localized in juvenile acatalasemic cells, whereas in normal and heterozygous individuals the catalase activity level does not alter significantly during the life span of the red cells. These findings agree with the observation that there is no gene dosage in heterozygotes, their catalase activity values falling within the normal range.  相似文献   

10.
The catalase activities in blood and organs of the acatalasemic (C3H/AnLCsbCsb) mouse of the C3H strain are lower than those of the normal (C3H/AnLCsaCsa) mouse. We conducted a study to examine changes in the activities of antioxidant enzymes, such as catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPX), the total gluathione content, and the lipid peroxide level in the brain, which is more sensitive to oxidative stress than other organs, at 3, 6, or 24 hr following X-ray irradiation at doses of 0.25, 0.5, or 5.0 Gy to the acatalasemic and the normal mice. No significant change in the lipid peroxide level in the acatalasemic mouse brain was seen under non-irradiation conditions. However, the acatalasemic mouse brain was more damaged than the normal mouse brain by excessive oxygen stress, such as a high-dose (5.0 Gy) X-ray. On the other hand, we found that, unlike 5.0 Gy X-ray, a relatively low-dose (0.5 Gy) irradiation specifically increased the activities of both catalase and GPX in the acatalasemic mouse brain making the activities closer to those in the normal mouse brain. These findings may indicate that the free radical reaction induced by the lack of catalase is more properly neutralized by low dose irradiation.  相似文献   

11.
The assembly and the use of a simple airtight pressurized reaction vessel are described for the measurement of catalase activity with a micro oxygen electrode in an optically heterogenous medium. The oxygen concentration is expressed as the ratio of observed current to the current in an air-saturated solution. Thus, an individual standard can be obtained for each measurement and the calibration is less affected by changes in the amplification factor. Different procedures for calibration of the oxygen electrode were compared. Specific activities of crystalline catalase, of red blood cells from humans and from normal or acatalasemic mice, and of liver homogenates from normal or amino-triazole-pretreated rats were determined. The specific catalase activity of human erythrocytes, as found by this method, agrees with that obtained photometrically.  相似文献   

12.
This paper concerns an enzymological investigation into a putative canine canalogue of the human autosomal recesive disease primary hyperoxaluria type 1 (alanine:glyoxylate / serine:pyruvate aminotransferase deficiency). The liver and kidney activities of alanine:glyoxylate aminotransferase and seribe:pyruvate aminotransferase in two Tibetan Spaniel pups with familial oxalate nephripathy were markedly reduced when compared with a variety of controls. There were no obvious deficiencies in a number of other enzymes including d-glycerate dehydrogenese / glyoxylate reductase which have been shown previously to be deficient in primary hyperoxaluria type 2. Immunoblotting of liver and kidney homogenates from oxalotic dogs also demonstrated a severe deficiency of immunoreactive alanine:glyoxylate aminotransferase. The developmental expression of alanine:glyoxylate / serine:pyruvate aminotransferase was studied in the livers and kidneys of control dogs. In the liver, enzyme activity and immunoreactive protein were virtually undetectable at 1 day old, but then increased to reach a plateau between 4 and 12 weeks. During this period the activity was similar to that found in normal humanb liver. The enzyme activities and the levels of immunoreactive protein in the kidneys were more erratic, but they appeared to increase up to 8 weeks and then decrease, so that by 36 weeks the levels were similar to those found at 1 day. The data presented in this paper suggest that these oxalotic dogs have a genetic condition that is anlogous, at least enzymologically, to the human disease primary hyperoxaluria type 1.  相似文献   

13.
Mycoplasma pulmonis, an etiological agent of murine pneumonia, produced about 0.065 mumoles of hydrogen peroxide (H(2)O(2)) per hr per 10(10) colony-forming units. When glucose was present at a concentration of 0.01 m, H(2)O(2) production was increased by 50%. To determine if H(2)O(2) production by M. pulmonis could be correlated with virulence, normal, acatalasemic, and acatalatic mice were infected with the organism. Three days after infection with M. pulmonis significantly more acatalatic mice had pneumonia than did normal or acatalasemic mice. The pneumonia in acatalatic mice was also more severe than in the other two groups. Five days after infection, pneumonia in the acatalatic mice was resolved, whereas normal mice were severely affected. The presence of pneumonia and the severity were correlated with the recovery of M. pulmonis from the lesions. In vitro studies of the effect of catalase on M. pulmonis showed that exogenously supplied catalase stimulated the growth of M. pulmonis at 37 C and prolonged its survival at 25 C. Hemolysis of sheep blood, guinea pig blood, rabbit blood, and normal and acatalasemic mouse blood by M. pulmonis was inversely related to the catalase activity of the erythrocytes. These findings suggest that H(2)O(2) secretion contributes to the virulence of M. pulmonis and to the death of the microorganism in the absence of host catalase.  相似文献   

14.
Tissue-specific catalase activity in 3-week-old animals from inbred mouse strains 129/ReJ, BALB/c, C3H/HeAnl/Cas-1b, C3H/HeSnJ, C3H/S, C57BL/6J, and Swiss-Webster was found to be highly variable by analysis of variance (P=0.01). Appropriate crosses were made among strains which were classified as normal (BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (129/ReJ, C57BL/6J), and acatalasemic (C3H/HeAnl/Cas-1b) with respect to blood catalase activity to study the inheritance of the blood, kidney, liver, and lung catalase activity levels in a number of generations (reciprocal F1's, F2, two backcrosses —BC1 and BC2— and some RI lines). Segregation analysis and statistical methods which tested different models of inheritance as well as calculations of heritability were used in an effort to assess and evaluate genetic parameters that affect catalase activity. Results indicate that the inheritance of blood catalase activity in the cross involving acatalasemic and normal (BALB/c, C3H/HeSnJ) strains is compatible with the single-locus difference between the parental strains; however, the difference between the acatalasemic and the hypocatalasemic strain (C57BL/6J) would require additional genetic interaction for a satisfactory explanation. A similar pattern of generalization also applies to the inheritance of kidney catalase activity. The segregation pattern for the liver and lung catalase activity in most crosses is significantly different from the expectations of the single locus model. These results are compatible with the concept that a number of genes must affect tissue-specific catalase activity in mice. These may include previously described (e.g., Ce-1 and Ce-2) or novel genetic regulators/modifiers which interact with a single structural gene (Cas-1) or its product to produce the catalase phenotype characteristic of specific tissues in each strain.This investigation was supported by a Natural Sciences and Engineering Research Council of Canada operating grant to S.M.S.  相似文献   

15.
This paper concerns an enzymological investigation into a putative canine analogue of the human autosomal recessive disease primary hyperoxaluria type 1 (alanine:glyoxylate/serine:pyruvate aminotransferase deficiency). The liver and kidney activities of alanine:glyoxylate aminotransferase and serine:pyruvate aminotransferase in two Tibetan Spaniel pups with familial oxalate nephropathy were markedly reduced when compared with a variety of controls. There were no obvious deficiencies in a number of other enzymes including D-glycerate dehydrogenase/glyoxylate reductase which have been shown previously to be deficient in primary hyperoxaluria type 2. Immunoblotting of liver and kidney homogenates from oxalotic dogs also demonstrated a severe deficiency of immunoreactive alanine:glyoxylate aminotransferase. The developmental expression of alanine:glyoxylate/serine:pyruvate aminotransferase was studied in the livers and kidneys of control dogs. In the liver, enzyme activity and immunoreactive protein were virtually undetectable at 1 day old, but then increased to reach a plateau between 4 and 12 weeks. During this period the activity was similar to that found in normal human liver. The enzyme activities and the levels of immunoreactive protein in the kidneys were more erratic, but they appeared to increase up to 8 weeks and then decrease, so that by 36 weeks the levels were similar to those found at 1 day. The data presented in this paper suggest that these oxalotic dogs have a genetic condition that is analogous, at least enzymologically, to the human disease primary hyperoxaluria type 1.  相似文献   

16.
Genetic control of the level of blood catalase activity was first demonstrated in 1927. At present, such control has been demonstrated or suggested for nine different species, including man, the most studied. The development of an acatalasemic strain of mice has permitted a wide variety of experimental approaches, including most of those used in humans. Among those approaches which cannot readily be applied to man but have been used in acatalasemic mice are investigations of sensitivity to radiation lethality, mechanism of awareness to radiation, possible use as a model for replacement therapy for inborn errors of metabolism, and catalase in tissues other than erythrocytes. These are described, together with genetic, immunological, and other studies comparable to similar work on acatalasemic humans.This paper was presented at a symposium entitled Genetic Control of Mammalian Metabolism held at The Jackson Laboratory, Bar Harbor, Maine, June 30–July 2, 1969. The symposium was supported in part by an allocation from NIH General Research Support Grant FR 05545 from the Division of Research Resources to The Jackson Laboratory.Work supported by the United States Atomic Energy Commission.  相似文献   

17.
为探讨低温对机体能量代谢、器官/组织抗氧化能力和过氧化自由基水平的影响及其内在联系,本研究测定了不同时间低温和梯度低温处理的黑线仓鼠的摄食量、体重、主要内脏器官/组织的过氧化物歧化酶(SOD)、过氧化氢酶(CAT)、H2O2和丙二醛(MDA)水平。低温使摄食量显著增加,但未影响体重。低温暴露42 d使心脏和骨骼肌MDA水平、骨骼肌SOD活性显著升高;梯度低温使脑和肾脏H2O2水平、肝脏和骨骼肌SOD活性显著降低,使脑、肝脏、肺、肾脏MDA水平、脑和小肠SOD活性显著升高。抗氧化能力和过氧化自由基水平在不同器官之间相关性存在差异,同一器官内二者的相关性在肾脏为100%,肝脏66.7%,骨骼肌50.0%。结果表明:(1)过氧化自由基的产生与低温暴露的时间和程度有关;(2)不同器官/组织过氧化自由基水平不同;(3)部分器官/组织抗氧化酶活性的变化与过氧化自由基水平的变化密切相关,可能是防止过氧化损伤的主要防御系统。  相似文献   

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The catalase activities in the blood and organs of the acatalasemic (C3H/AnLCsb-Csb) mouse of the C3H strain are lower than those of the normal (C3H/AnLCSa-Csa) mouse. We examined the effects of post low-dose (0.5 Gy) X-ray irradiation which reduced the oxidative damage under carbon tetrachloride-induced hepatopathy in acatalasemic or normal mice. As a result, the 0.5 Gy irradiation after carbon tetrachloride administration decreased the glutamic oxaloacetic and glutamic pyruvic transaminase activity in the acatalasemic mouse blood to a level similar to that of the acatalasemic mouse blood not treated with carbon tetrachloride; this is in contrast to a high-dose (15 Gy) irradiation. In the same manner, pathological disorder was improved by 0.5 Gy irradiation. The fat degeneration in normal mice was quickly reduced, in contrast to acatalasemic mice. These findings suggest that low-dose irradiation after carbon tetrachloride administration accelerates the rate of recovery and that catalase plays an important role in the recovery from hepatopathy induced by carbon tetrachloride, in contrast to high-dose irradiation.  相似文献   

20.
The methanol metabolism in acatalasemic mice was studied by administering [14C]methanol and [14C]formic acid to acatalasemic and normal mice and determining the radioactivity of exhaled carbon dioxide. Methanol metabolism was also studied in acatalasemic and normal mice treated with 3-amino-1,2,4-triazole (AT), which is known to be an inhibitor of catalase (EC 1.11.1.6). The metabolism of methanol and formic acid was inhibited in acatalasemic mice as seen by reduced [14C]CO2 production. Similar results were obtained when AT was given prior to the methanol injection into the normal and acatalasemic mice. The results indicate the peroxidative activity of catalase plays the major role in the methanol metabolism in mice. On the other hand similar studies with [1-14C] ethanol showed that the metabolism of ethanol was not inhibited in acatalasemic mice.  相似文献   

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