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PubMed1988

Micromethods in single muscle fibers. 1. Determination of catalase and superoxide dismutase.

Methods have been developed for the measurements of catalase and superoxide dismutase (SOD) in single, isolated muscle fibers. These fibers are also classified according to fiber type. Catalase is determined using a fluorescent method for the measurement of hydrogen peroxide consumed. SOD measurements are carried out using a modification of established techniques whereby the inhibition of oxidation of epinephrine by SOD is assayed fluorometrically. Both enzymes may be determined in submicrogram samples of dried muscle. This approach avoids the complication of the inclusion of nonmuscle tissue with varying enzymatic activities which is frequently experienced when using homogenates of muscle, particularly diseased muscle. In addition, these techniques can be used to determine the inherent variation in SOD and catalase activities within individual fibers of the same fiber type. The Km and Vmax for catalase, determined using homogenates of human muscle, were found to be 12 mM and 1.45 mumol/min/mg dry wt, respectively. Catalase of muscle was inhibited 50% by 2 microM sodium azide. Mn-SOD contributes less than one-fifth of the total SOD activity. Therefore the activity is largely due to the Cu-Zn form of SOD. These methods are applicable to a wide variety of tissues.

Catalase↗
PubMed1990

On the application of the Clark oxygen electrode to the study of enzyme kinetics in apolar solvents: the catalase reaction.

A method for recording O2 concentrations in nonconducting organic media with the Clark oxygen electrode was developed. Spontaneous oxidation of Na2S2O4 and the enzymatic reduction of NaBO3 or H2O2 by bovine liver catalase trapped in hydrated micelles of dioctylsulfosuccinate (AOT)/toluene were used as model systems. O2 titration with the above systems showed that air-saturated 1.6 M H2O/0.2 M AOT/toluene media contain seven times more O2 (1.4 mM) than aqueous solutions (0.2 mM). The measured Km values of catalase for NaBO3 and H2O2 in organic media were Kmov = 15 and 17 mM, respectively, whereas in aqueous buffer the values were 45 and 54 mM. In the toluene media, catalase activity increased with the W0 (H2O/AOT molar ratio) of the micellar preparation, reaching maximal activity at W0 = 10-12; under this condition, the catalytic center activity (Kp) of H2O2 was 7 x 10(6) min-1, similar to that obtained in the aqueous buffer (H2O2 = 7 x 10(6) min-1). It was found that the optimal pH for catalase in toluene media (pH 8.0) was shifted 1.0 unit compared to that in the aqueous buffer (pH 7.0). On the other hand, catalase was severely inhibited by NaN3 in both media. Thus, polarography based on the Clark oxygen electrode seems to be an easy, rapid, and sensitive technique for studying enzyme reactions consuming or evolving O2 in apolar media.

Animals↗
PubMed1990

Biogenesis of catalase in glyoxysomes and leaf-type peroxisomes of sunflower cotyledons.

Eight charge isoforms of catalase (EC 1.11.1.6.) appeared in the peroxisomes of sunflower cotyledons during growth after germination (2.5 days of dark, continuous light thereafter). In the light, when glyoxysomes were transformed to leaf-type peroxisomes, the five more-basic forms (CAT 1 through CAT 5) became more prominent, while amounts of the three more-acidic forms (CAT 6 through CAT 8) decreased considerably. The isoforms CAT 1 through CAT 5 were hybrids of 55- and 59-kDa subunits, whereas CAT 6 through CAT 8 contained 55-kDa subunits exclusively. The catalase translation products changed during the transition of glyoxysomes to leaf-type peroxisomes. Polyadenylated RNA from 2-day-old cotyledons directed synthesis of 56-kDa subunits, whereas 59-kDa subunits predominated after in vitro translation of RNA from 4-day-old cotyledons. Both translation products were processed to lower molecular weight forms in vivo. The 56-kDa translation products were precursors for 55-kDa subunits in glyoxysomes. It could not be decided however, whether the 59-kDa precursors were processed to 56-kDa or 55-kDa subunits, because both subunits of lower molecular weight were present in leaf-type peroxisomes. Some of the 59-kDa precursors escaped proteolytic processing and formed hybrid isoforms (CAT 1 through CAT 5) with mature 55-kDa subunits. This type of isoform formation, i.e., condensation of mature and unprocessed subunits, has not yet been described for other plant catalases. In summary, the results showed that the postgerminative changes in the number and abundance of catalase isoforms resulted from changes in translation (transcription) of catalase precursors and assembly of proteolytically processed and unprocessed subunits into tetramers within peroxisomes acquiring leaf peroxisomal function.

Catalase↗
PubMed1991

Two genes encode the two subunits of cottonseed catalase.

The isolation and sequence of a cDNA encoding a developmentally distinct subunit of cottonseed catalase are presented. A 1.8-kb cDNA was selected from a cDNA library constructed with poly(A)+ RNA isolated from 3-day-old dark-grown cotyledons in which a second subunit (designated SU 2 in an earlier publication) of catalase was predominantly synthesized. The cDNA encodes a 492-amino acid peptide with a calculated Mr of 56,900. The nucleotide sequence is 76% identical to a cDNA encoding another subunit (SU 1) which was predominantly synthesized in 1-day-old-cotyledons. Most of the divergence occurs in the 5' and 3' non-coding regions, and at the third positions of the codons. The deduced amino acid sequence is 92% identical to that of SU 1. Denaturing isoelectric focusing and SDS-PAGE of products transcribed and translated in vitro from these cDNAs revealed that the cDNA selected from the "1-day" library encoded SU 1 and the cDNA selected from the "3-day" library (this paper) encoded SU 2 of catalase. These data and results from Southern blot analyses of genomic DNA indicate that there are two genes encoding catalase subunits in cotton cotyledons, with only one copy of SU 1 and at least two copies of SU 2 in the genome. A peroxisomal targeting signal, e.g., Ser-Lys-Leu, is not located at the C-terminus of either subunit, or within 25 residues of the C-terminus of SU 1, although it occurs at six residues upstream from the C-terminus of SU 2. A possible location of a targeting sequence for catalase and other peroxisomal proteins lacking the C-terminal tripeptide motif is proposed.

Amino Acid Sequence↗
PubMed1985

Influence of endogenous catalase activity on the sensitivity of the oral bacterium Actinobacillus actinomycetemcomitans and the oral haemophili to the bactericidal properties of hydrogen peroxide.

Actinobacillus actinomycetemcomitans and the genetically-related oral haemophili (Haemophilus segnis, Haemophilus aprhophilus and Haemophilus paraphrophilus) exhibit a range of sensitivities to the lethal effect of hydrogen peroxide (H2O2), A. actinomycetemcomitans being the most resistant. To extend this information, susceptibility to a range of H2O2 concentrations (10(-6)-10(-3) M) was assessed by incubating bacterial suspensions for 1 h at 37 degrees C in the presence of H2O2 and spreading the suspensions on chocolate agar plates to determine the concentration of H2O2 producing a 50 per cent reduction in colony-forming units (LD50). Catalase activity was quantified with a Clark-type oxygen electrode, which polarographically monitored the formation of dissolved oxygen in bacterial suspensions or sonicates following addition of reagent H2O2. Sensitivity to H2O2 did not correlate with catalase activity, either in intact cells or in bacterial sonicates. Specifically, some bacterial strains with undetectable catalase activity were highly resistant to H2O2. Micromolar concentrations of sodium azide which completely inhibited cell-associated catalase activity did not affect the resistance of A. actinomycetemcomitans to H2O2. Thus, the endogenous catalase activity of A. actinomycetemcomitans and certain oral haemophili is not an important determinant of resistance to the bactericidal effects of H2O2.

Actinobacillus↗
PubMed1987

Hydrogen peroxide elicits activation of bovine pulmonary arterial soluble guanylate cyclase by a mechanism associated with its metabolism by catalase.

Guanylate cyclase activity in the soluble extract of bovine pulmonary arteries is activated by hydrogen peroxide generated by glucose oxidase only in the presence of catalase. This mechanism of guanylate cyclase activation is not blocked by scavengers for superoxide anion or hydroxyl radical, but is selectively inhibited by methylene blue, inactivation of catalase and ethanol. The time dependency of increases in guanylate cyclase activity in the presence of peroxides that are substrates for catalase are associated with the spectral detection of compound I, a species of catalase formed during the metabolism of peroxide. Thus, activation of soluble guanylate cyclase appears to be elicited by compound I of catalase or by a mediator generated by this species.

Animals↗
PubMed1992

Depression of catalase gene expression in the liver of tumor bearing nude mice.

Based on the classical observation that catalase activity is reduced in the liver of a tumor bearing host, we studied this phenomenon from the aspect of gene expression. Northern blot analysis on the livers of mice with a rat tumor showed that the catalase gene expression is lowered in a tumor size-dependent fashion. Decreased gene expression was also seen irrespective of tissue or species origin of tumors transplanted. Removal of the implanted tumor resulted in restoration of the reduced gene message to the normal level. The tumor effect on the catalase gene expression was shown to be controlled at the transcriptional level. These results strongly suggest that the reduction of liver catalase activity in the tumor bearer may be due to down regulation of the catalase gene induced in the liver by a certain humoral factor(s) from the transplanted tumor.

Animals↗
PubMed1986

Differential inhibition of rat tissue catalase by cyanamide.

The relative sensitivity of rat tissue catalase to inhibition by intraperitoneally administered cyanamide was liver greater than kidney greater than heart greater than brain, whereas the activity of the erythrocyte enzyme was affected minimally. The measured ED50 values for cyanamide in these tissues were 31, 44, 107 and 680 mumoles/kg body weight for liver, kidney, heart and brain respectively. On a molar basis, cyanamide was approximately twenty times more potent than 3-amino-1,2,4-triazole (3-AT) in inhibiting hepatic catalase in vivo in the rat. Like 3-AT, cyanamide inhibited erythrocyte catalase activity in vitro in the presence of hydrogen peroxide. The apparent similarities between the inhibition of hepatic catalase by cyanamide and 3-AT in vivo suggest that cyanamide belongs to the family of 3-AT-like catalase inhibitors.

Amitrole↗
PubMed1992

Three-dimensional structure of catalase from Micrococcus lysodeikticus at 1.5 A resolution.

The three-dimensional crystal structure of catalase from Micrococcus lysodeikticus has been solved by multiple isomorphous replacement and refined at 1.5 A resolution. The subunit of the tetrameric molecule of 222 symmetry consists of a single polypeptide chain of about 500 amino acid residues and one haem group. The crystals belong to space group P4(2)2(1)2 with unit cell parameters a = b = 106.7 A, c = 106.3 A, and there is one subunit of the tetramer per asymmetric unit. The amino acid sequence has been tentatively determined by computer graphics model building and comparison with the known three-dimensional structure of beef liver catalase and sequences of several other catalases. The atomic model has been refined by Hendrickson and Konnert's least-squares minimisation against 94,315 reflections between 8 A and 1.5 A. The final model consists of 3,977 non-hydrogen atoms of the protein and haem group, 426 water molecules and one sulphate ion. The secondary and tertiary structures of the bacterial catalase have been analyzed and a comparison with the structure of beef liver catalase has been made.

Amino Acid Sequence↗
PubMed1992

Is the cytosolic catalase induced by peroxisome proliferators in mouse liver on its way to the peroxisomes?

Dietary treatment of male C57B1/6 mice with clofibrate, nafenopin or WY-14.643 resulted in a modest (at most 2-fold) increase in the total catalase activity in the whole homogenate and mitochondrial fraction prepared from the livers of these animals. On the other hand, the catalase activity recovered in the cytosolic fraction was increased 12- to 18-fold, i.e. 30-35% of the total catalase activity in the hepatic homogenate was present in the high-speed supernatant fraction after treatment with these peroxisome proliferators. A study of the time course of the changes in peroxisomal and cytosolic catalase activities demonstrated that the peroxisomal activity both increased upon initiation of exposure and decreased after termination of treatment several days after the increase and decrease, respectively, in the corresponding cytosolic activity. This finding suggests that the cytosolic catalase may be on its way to incorporation into peroxisomes.

Animals↗
PubMed1995

Comparative analysis of catalases: spectral evidence against heme-bound water for the solution enzymes.

A recent X-ray structural analysis of M. luteus catalase indicates heme-bound H2O trans to the proximal tyrosinate ligand, a finding in contrast to previous X-ray data reporting a 5-coordinate heme for bovine liver catalase. The presence of heme-bound H2O, requiring displacement prior to substrate-binding, is likely to be catalytically significant for catalases. We have used magnetic circular dichroism (MCD) spectroscopy, a highly accurate method for assignment of heme spin- and coordination-states, to study native, solution forms of bovine liver, M. luteus, and A. niger catalases. All three enzymes display similar spectral features with the weak (approximately 5 delta epsilon M [moles.cm.Tesla]-1) intensity typical of a 5-coordinate high-spin ferric heme. No evidence for H2O-ligation, inducing a 6-coordinate heme, occurred upon variation of pH or buffer composition. Therefore, we suggest that the catalytically significant structure of catalases has an unoccupied heme binding site trans to the proximal tyrosinate heme ligand.

Animals↗
PubMed1983

On the synthesis and incorporation of catalase and urate oxidase into the peroxisomes of mouse liver.

The processes associated with the biogenesis of peroxisomes in mouse liver have been studied by following the incorporation of radiolabelled leucine into major enzymic components of this organelle. Maximal incorporation of label into peroxisomal catalase and urate oxidase occurred within 2 hr, with the urate oxidase being labelled before catalase, but subsequent to the incorporation of phospholipid into this organelle. Subsequently, immunoprecipitation of catalase from the large granular fraction of mouse liver was shown to result in the isolation of a catalase molecule which had lost a peptide of approx. 2000 dalton from each subunit by comparison with the newly-synthesized enzyme. It was observed that the modification of catalase was obviated by the presence of leupeptin and iodoacetamide and this information has enabled the purification of both modified and unmodified forms of the enzyme. The possible significance of these data has been discussed and the major features incorporated into a working model of peroxisomal biogenesis.

Animals↗
PubMed1988

Effect of chronic ethanol treatment under partial catalase inhibition on the activity of enzymes related to peroxide metabolism in rat liver and heart.

1. In order to test the hypothesis that the alcoholic cardiomyopathy under partial catalase inhibition is associated with the activation of lipid peroxidation in cardiomyocytes (Panchenko et al., Experientia 43, 580-581, 1987), the effects of ethanol and catalase inhibitor 3-amino-1,2,4-triazole (aminotriazole) on rat heart and liver content of reduced glutathione and on the activity of enzymes related to peroxide metabolism: catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and glucose-6-phosphate dehydrogenase were investigated. 2. In accordance with the data obtained by Kino (J. molec, cell. Cardiol. 13, 5-12, 1981), when ethanol (36% of dietary calories) and aminotriazole were simultaneously administered an alcoholic cardiomyopathy developed while in the liver moderate fatty degeneration was revealed. 3. Chronic combined or separate administration of ethanol and aminotriazole was shown to increase glutathione concentration and glutathione-S-transferase activity in rat liver. In the groups of animals which received isocaloric carbohydrates in the diet instead of ethanol the liver glucose-6-phosphate dehydrogenase was increased. 4. Acute and chronic aminotriazole injections led to catalase inactivation and in the latter case also to inhibition of the liver superoxide dismutase and glutathione peroxidase activities. 5. Ethanol and aminotriazole treatment did not alter the glutathione level and the activity of all enzymes tested (except catalase) in rat myocardium.

Amitrole↗
PubMed1985

The active center of catalase.

The refined structure of beef liver catalase (I. Fita, A. M. Silva, M. R. N. Murthy & M. G. Rossmann, unpublished results) is here examined with regard to possible catalytic mechanisms. The distal side of the deeply buried heme pocket is connected with the surface of the molecule by one (or possibly two) channel. The electron density representing the heme group, in each of the two crystallographically independent subunits, is consistent with degradation of the porphyrin rings. The heme group appears to be buckled, reflecting the high content of bile pigment in liver catalase. The spatial organization on the proximal side (where the fifth ligand of the iron is located) shows an elaborate network of interactions. The distal side contains the substrate pocket. The limited space in this region severely constrains possible substrate positions and orientations. The N delta atom of the essential His74 residue hydrogen bonds with O gamma of Ser113, which in turn hydrogen bonds to a water molecule associated with the propionic carbonylic group of pyrrole III. These interactions are also visible in the refined structure of Penicillium vitale catalase (B. K. Vainshtein, W. R. Melik-Adamyan, V. V. Barynin, A. A. Vagin, A. I. Grebenko, V. V. Borisov, K. S. Bartels, I. Fita, & M. G. Rossmann, unpublished results). Model building suggests a pathway for a catalase mechanism (compound I formation, as well as catalatic and peroxidatic reactions). There are some similarities in compound I formation of catalase and cytochrome c peroxidase.

Amino Acid Sequence↗
PubMed1986

Protection against oxygen-induced reperfusion injury of the isolated canine heart by superoxide dismutase and catalase.

While oxygen-derived free radicals have been implicated in the pathogenesis of myocardial injury, the exact nature of this injury is still unclear. To test the hypothesis that oxygen-induced injury may influence the recovery of cardiac function from ischemic damage, we used an oxygen free radical scavenger, superoxide dismutase (SOD), together with catalase, during the reperfusion of isolated canine heart which had been subjected to 15 min of normothermic ischemic arrest followed by 2 hr of hypothermic cardioplegic preservation using a modified Collins solution. Determinations of thiobarbituric acid reactive substances and coenzyme Q10 within the myocardium showed that the treatment with SOD and catalase was capable of inhibiting lipid peroxidation induced by reperfusion. This inhibition was apparently associated with the improvement of myocardial energy metabolism and cardiac performance. Coronary flow was significantly higher in the heart treated with SOD and catalase during the working stage with a corresponding increase in oxygen consumption. Myocardial adenosine triphosphate (ATP) was partially, but significantly restored during reperfusion in these hearts whereas no restoration was observed in the heart without the enzymes. The treatment with SOD and catalase also improved left ventricular stroke work index and left ventricular maximum dp/dt at an early stage of the working mode. These results suggest that the use of SOD and catalase during reperfusion can protect the ischemic heart against reperfusion injury by scavenging oxygen-derived free radicals.

Animals↗
PubMed1995

Catalase activity as a predictor of amniotic fluid culture results in preterm labor or premature rupture of membranes.

OBJECTIVE: To evaluate catalase activity as a rapid predictor of microbial invasion of amniotic fluid (AF). METHODS: The study population consisted of 74 patients before 36 weeks' gestation with preterm labor or premature rupture of membranes (PROM). Subjects were excluded if there was evidence of clinical chorioamnionitis or fetal distress at admission. Amniocentesis was done within 24 hours of admission, and the AF was cultured for aerobic and anaerobic bacteria and for Mycoplasma species. All AF samples were Gram stained, and slides were examined by microbiology technologists. Amniotic fluid catalase activity was measured immediately after amniocentesis using a commercially available kit. The sensitivity of the Gram stain and catalase activity were compared using McNemar exact test. RESULTS: Amniotic fluid cultures were positive in 12 of 37 (32%) patients presenting with preterm labor and in 21 of 37 (56%) patients with PROM. Catalase activity was significantly more sensitive than Gram stain in detecting positive AF cultures in cases of PROM (P < .001) and preterm labor (P < .04). CONCLUSION: Catalase activity is a simple, rapid test that is useful in identifying subclinical intra-amniotic infection in patients with preterm labor or PROM.

Amniotic Fluid↗
PubMed1976

Simple screening test for significant bacteriuria in urine. Catalase determination by disk flotation method.

Colony count cultures and catalase determinations were done on 294 urine samples in two series of patients at Royal Victoria Hospital. Thirty-six specimens were reported to be positive by colony count and by catalase determination. A total of 135 specimens found to be negative by colony count were also negative by the disk flotation test. Catalase activity in 4 urines reported as false negative were found to contain 6,000 or less colonies per ml. More than 50 per cent of the false positive results could be attributed to the presence of red blood cells. Data were insufficient to explain the remaining false positive catalase determinations. However, catalase determinations by the disk flotation method proved to be a successful screening test for significant bacteriuria.

Bacteriuria↗
PubMed1992

High production of catalase in hydrogen peroxide-resistant human leukemia HL-60 cell lines.

The catalase activities of HP50-2 and HP100-1 cells, which are H2O2-resistant cell lines derived from human leukemia HL-60 cells, were 3 and 18 times higher, respectively, than that of HL-60 cells. These catalase activities of the resistant cells were precipitated with anti-catalase serum. The glutathione peroxidase activity of HP50-2 cells was about twice that of HL-60 or HP100-1 cells. The superoxide dismutase activities of HP50-2 and HP100-1 cells were, respectively, about 4 and 2 times that of HL-60 cells. In addition, both the resistant cell lines were completely devoid of myeloperoxidase activity. Pulse-labeling experiments showed that the syntheses of catalase in HP50-2 and HP100-1 cells were, respectively, 2 and 4 times that in HL-60 cells, and that, unlike the parent cells, neither line synthesized myeloperoxidase. Thus the alteration of catalase, glutathione peroxidase, and superoxide dismutase activity could be linked to the resistance of H2O2 of human leukemia cells.

Catalase↗