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1.
ABSTRACT

Antioxidant enzymes are essential proteins that maintain cell proliferation potential by protecting against oxidative stress. They are present in many organisms including harmful algal bloom (HAB) species. We previously identified the antioxidant enzyme 2-Cys peroxiredoxin (PRX) in the raphidophyte Chattonella marina. This enzyme specifically decomposes a hydrogen peroxide (H2O2). PRX is the only antioxidant enzyme so far identified in C. marina. This study used mRNA-seq, using Trinity assemble and blastx for annotation, to identify a further five antioxidant enzymes from C. marina: Cu Zn superoxide dismutase (Cu/Zn-SOD), glutathione peroxidase (GPX), catalase (CAT), ascorbate peroxidase (APX) and thioredoxin (TRX). In the gene expression analysis of six enzymes (Cu/Zn-SOD, GPX, CAT, APX, TRX and PRX) using light-acclimated (100 μmol photons m?2 s?1) C. marina cells, only PRX gene expression levels were significantly increased by strong light irradiation (1000 μmol photons m?2 s?1). H2O2 concentration and scavenging activity were also increased and significantly positively correlated with PRX gene expression levels. In dark-acclimated cells, expression levels of all antioxidant enzymes except APX were significantly increased by light irradiation (100 μmol photons m?2 s?1). Expression decreased the following day, with the exception of PRX expression. With the exception of CAT, gene expression of antioxidant enzymes was not significantly induced by artificial H2O2 treatment, although average gene expression levels were slightly increased in some enzymes. Thus, we suggest that light is the main trigger of gene expression, but the resultant oxidative stress is also a possible factor affecting the gene expression of antioxidant enzymes in C. marina.  相似文献   

2.
Catalase is well known as capable of inducing the decomposition of H2O2. In this study, a kind of immobilized catalase (entrapped in cross-linked chitosan beads) was dispersed in conventional acetate filter as an antioxidant additive. Quantitative estimation of the free radicals in mainstream cigarette smoke (MCS) was performed to address the effect of this modified filter. It was found that the levels of PBN adduct and NO?/NO2? associated with the gas-phase mainstream cigarette smoke (GPCS) were efficiently decreased by ~40% through catalase filtering. Besides, the modified filter was found to lower the MCS-induced adverse biological effects including lipid peroxidation and mutagenicity. This was proved to be substantially attributed to the catalase-dependent breakdown of NO?, which was stimulated by some of peroxides (most probably being H2O2), the dismutation products of tar particulate matters (TPM). These results highlighted a promising approach to reduce the smoking-associated health risks to passive smokers. Moreover, the mechanisms of catalase filtering may be helpful for the development of appropriate immobilized enzyme systems to be applied for reducing health risks associated with gaseous pollutants.  相似文献   

3.
NO (nitric oxide) and H2O2 (hydrogen peroxide) are important signaling molecule in plants. Brassica napus L. was used to understand oligochitosan inducing production of NO (nitric oxide) and H2O2 (hydrogen peroxide) and their physiological function. The result showed that the production of NO and H2O2 in epidermal cells of B. napus L. was induced with oligochitosan by fluorescence microscope. And it was proved that there was an interaction between NO and H2O2 with L-NAME (NG-nitro-l-arg-methyl eater), which is an inhibitor of NOS (NO synthase) in mammalian cells that also inhibits plant NO synthesis, and CAT (catalase), which is an important H2O2 scavenger, respectively. It was found that NO and H2O2 induced by oligochitosan took part in inducing reduction in stomatal aperture and LEA protein gene expression of leaves of B. napus L. All these results showed that oligochitosan have potential activities of improving resistance to water stress.  相似文献   

4.
Abstract

This veterinary study is aimed at further standardization of H2O2 and pH measurements in exhaled breath condensate (EBC). Data obtained in the study provide valuable information for many mammalian species including humans, and may help to avoid general pitfalls in interpretation of EBC data. EBC was sampled via the ‘ECoScreen’ in healthy calves (body weight 63–98 kg). Serum samples and condensates of ambient (indoor) air were collected in parallel. In the study on H2O2, concentrations of H2O2 in EBC, blood and ambient air were determined with the biosensor system ‘ECoCheck’. In EBC, the concentration of H2O2 was found to be dependent on food intake and increased significantly in the course of the day. Physiologically, lowest H2O2 concentrations at 06:00 varied within the range 138–624 nmol l?1 EBC or 0.10–0.94 nmol per 100 l exhaled breath and individual concentrations were significantly different indicating a remarkable intersubject variability. Highly reproducible results were seen within each subject (three different days within 4 weeks). No correlation existed between H2O2 concentrations in EBC and blood, and EBC–H2O2 was not influenced by variables of spontaneous breathing. Further results confirmed that standardization of H2O2 measurements in EBC requires (1) the re-calculation of the concentration exhaled per 100 l exhaled breath (because the analyzed concentration in the liquid condensate underlies multiple methodological sources of variability given by the collection process), and (2) subtracting the concentration of inspired indoor H2O2. In the study on pH use of the ISFET electrode (Sentron, the Netherlands) and a blood gas analyzer ABL 550 (Radiometer, Denmark) led to comparable results for EBC–pH (r=0.89, R2=79.3%, p≤0.001). Physiological pH data in non-degassed EBC samples varied between 5.3 and 6.5, and were not significantly different between subjects, but were significantly higher in the evening compared with the morning. EBC–pH was not dependent on variables of spontaneous breathing pattern or ambient conditions, and no significant correlation was found between serum and EBC for pH.  相似文献   

5.
Differential expression of catalase isozymes in different genotypes of chickpea resistant genotypes- A1, JG-315, JG-11, WR-315, R1-315, Vijaya, ICCV-15017, GBS-964, GBM-10, and susceptible genotypes- JG-62, MNK, ICCV-08321, ICCV-08311, KW-104, ICCV-08123, ICC-4951, ICC-11322, ICC-08116 for wilt disease caused by Fusarium oxysporum. f. sp. ciceri (Foc) was analyzed. Salicylic acid (SA) and H2O2 concentrations were determined in control as well as in plants infected with F. ciceri and found that the high and low levels of salicylic acid and H2O2 in resistant and susceptible genotypes of chickpea respectively. Catalase isozyme activities were detected in the gel and found that no induction of new catalases was observed in all the resistant genotypes and their some of the native catalase isozymes were inhibited; whereas, induction of multiple catalase isozymes was observed in all the screened susceptible genotypes and their activities were not inhibited upon Foc or SA treatments. The above results support the possible role of these isozymes as a marker to identify which genotype of chickpea is expressing systemic acquired resistance.  相似文献   

6.
The present study was performed to see the physiological role of cytosolic ascorbate peroxidase (APX) and its relationship to other enzymes involved in the H2O2 scavenging metabolism, and also to elucidate the regulation of APX expression in dark-grown radish (Raphanus sativus L. cv Taiwang) cotyledons. To do so, 3-amino-l,2,4-triazole (aminotriazole), a known specific inhibitor of catalase, was used to simulate a catalase-deficient phenomenon in cotyledons. Aminotriazole, in very low concetration (10-4 M), inhibited remarkably the development of catalase activity in cotyledons during dark germination. This inhibition of catalase by aminotriazole, however, did not result in any significant changes in the growth response and the H2O2 level of developing cotyledons. In addition, the development of guaiacol peroxidase (GPX) activity was also not significantly affected. Unlike GPX, cytosolic APX activity was induced rapidly and reached a 1.7-fold increase in aminotriazole treated cotyledons at day 7 after germination. However,in vitro incubation of cytosolic APX preparation from cotyledons with aminotriazole did not result in any significant change in activity. One cytosolic APX isozyme (APXa) band involved in this APX activation was predominantly intensified in a native polyacrylamide gel by activity staining assay. This means that this APXa isozyme seems to play a key role in the expression of cytosolic APX activity. On the other hand, 2-day-old control seedlings treated with exogenous 1 mM H2O2 for 1 h showed a significant increase of cytosolic APX acitivity even in the absence of aminotriazole. Also, 2 μM cycloheximide treatment substantially inhibited the increase of APX activity due to aminotriazole. Based on these results, we suggest that a radish cytosolic APX could probably be substituted for catalase in H2O2 removal and that the expression of APX seems to be regulated by a change of endogenous H2O2 level which couples to APX protein synthesis in a translation stage in cotyledons.  相似文献   

7.
Kolla VA  Vavasseur A  Raghavendra AS 《Planta》2007,225(6):1421-1429
The presence of 2 mM bicarbonate in the incubation medium induced stomatal closure in abaxial epidermis of Arabidopsis. Exposure to 2 mM bicarbonate elevated the levels of H2O2 in guard cells within 5 min, as indicated by the fluorescent probe, dichlorofluorescein diacetate (H2DCF-DA). Bicarbonate-induced stomatal closure as well as H2O2 production were restricted by exogenous catalase or diphenylene iodonium (DPI, an inhibitor of NAD(P)H oxidase). The reduced sensitivity of stomata to bicarbonate and H2O2 production in homozygous atrbohD/F double mutant of Arabidopsis confirmed that NADP(H) oxidase is involved during bicarbonate induced ROS production in guard cells. The production of H2O2 was quicker and greater with ABA than that with bicarbonate. Such pattern of H2O2 production may be one of the reasons for ABA being more effective than bicarbonate, in promoting stomatal closure. Our results demonstrate that H2O2 is an essential secondary messenger during bicarbonate induced stomatal closure in Arabidopsis.  相似文献   

8.
We optimized the conditions for isolation of extracellular catalases from Penicillium piceum F-648 and P. piceum A3 by means of volume chromatography with cadmium hydroxide gel. Our study showed that 55–57 mg wet gel are sufficient for the maximum sorption of catalase from 1 ml of culture fluid. This gel was formed in 1 ml 70 mM Cd(NO3)2 after addition of NaOH (Cd(NO3)2/NaOH molar ratio 1: 2.2). The eluting solution contained 50 mM NaH2PO4(pH 7.0), 5.0 mM dithiothreitol, and 0.3% sodium cholate and was potent in desorbing catalase from the gel. Subsequent ultrafiltration of the eluate on the membrane with a retention limit of 50 kDa allowed us to concentrate and purify the sample from low-molecular-weight protein impurities. NH4Cl (1.0 M) containing 0.3% sodium cholate was used to wash the sample from low-molecular-weight aromatic metabolites. Purified catalases included 33–34% antiparallel β-structures and 9%-spirals. Under optimal conditions in the medium of 10 mM phosphate buffered saline (pH 7.0) at 30°C, catalases from P. piceum F-648 were characterized by the following parameters: K M, 158.8 mM; catalytic constant, 2.83 × 106 s?1; enzyme inactivation rate constant in H2O2 decomposition, 3.5 × 10?2 s?1; and constant of the interaction between catalase complex I and second molecule of H2O2, 1.8 × 107M?1 s?1.  相似文献   

9.
Extracellular catalases produced by fungi of the genusPenicillium, i.e.,P. piceum, P. varians, andP. kapuscinskii, were purified by consecutive filtration of culture liquids. The maximum reaction rate of H2O2 decomposition, the Michaelis constants, and specific catalytic activities of isolated catalases were determined. The operational stability was characterized by the effective rate of catalase inactivation during enzymatic reaction (k in at 30°C). The thermal stability was determined by the rate of enzyme thermal inactivation at 45°C (k in * , s-1). Catalase fromP. piceum displayed the maximum activity, which was higher than the activity of catalase from bovine liver. The operational stability of catalase fromP. piceum was twofold to threefold higher than the stability of catalase from bovine liver. The physicochemical characteristics of catalases of fungi are better than the characteristics of catalase from bovine liver and intracellular catalase of yeastC. boidinii.  相似文献   

10.
Yeast cytochrome c peroxidase (CCP) efficiently catalyzes the reduction of H2O2 to H2O 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 (ccp1Δ) 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 H2O2. Transformation of ccp1Δ with ccp1W191F, which encodes the CCPW191F mutant enzyme lacking CCP activity, significantly increased the sensitivity to H2O2 of exponential-phase fermenting cells. In contrast, stationary-phase (7-day) ccp1Δ-ccp1W191F exhibited wild-type tolerance to H2O2, which exceeded that of ccp1Δ. Challenge with H2O2 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 ccp1Δ exhibited the highest catalase and glutathione reductase activities, a greater loss of these antioxidant activities was observed on H2O2 exposure in ccp1Δ than in ccp1Δ-ccp1W191F and wild-type cells. The phenotypic differences reported here between the ccp1Δ and ccp1Δ-ccp1W191F strains lacking CCP activity provide strong evidence that CCP has separate antioxidant and signaling functions in yeast.  相似文献   

11.
12.
Ghost crabs Ocypode ceratophthalmus were exercised in air and water to measure CO2 and O2 exchange rates using the method of instantaneous measurements of oxygen consumption rate (MO2) where applicable. Average heart rate increased from 100 to nearly 400 pulses per minute after five minutes of exercise on a treadmill at a run rate of 0.133 m s?1. It took less than a minute for oxygen taken up through the lung epithelium from the air inside the branchial cavity to reach the maximal oxygen consumption rate of 26.1 mmol O2 kg?1 h?1. Resting MO2 was 4.06 mmol O2 kg?1 h?1 in air, but decreased to 3.37 mmol O2 kg?1 h?1 in seawater. Radioactive CO2 from injected l-lactate is released linearly by the lung. The percent accumulated 14-CO2 in exhaled air, plotted against time, intersects zero time on the x -axis, indicating rapid gas exchange at the lung surface. The P 50 values for native haemocyanin of 4.89 mm Hg before exercise, and 8.99 mm Hg after exercise, are typical of a high-affinity haemocyanin usually associated with terrestrial crabs. The current notion that Ocypode ceratophthalmus drown when submerged in seawater was not substantiated by our experiments. MO2 in seawater increased from 3.37 mmol O2 kg?1 h?1 for resting crabs to 5.72 mmol O2 kg?1 h?1 during exercise. When submerged by wave-seawater in the natural environment and during exercise in respirometer-seawater O. ceratophthalmus do not swim but, having a specific density of 1.044, float nearly weightless with a minimum of body movements.  相似文献   

13.
《Free radical research》2013,47(1):205-210
Using the direct method of pulse radiolysis to determine the superoxide dismutase like activity of copper(II) cimetidine complexes, it was found that the reaction rate constant with O?2, kcat, was (8.5 ± 0.5) × 108 M?1s?1 independent of the cimetidine concentrations present in excess of 50–200 μM over the metal. The results suggest that either the 1:1 ligand to metal complex does not catalyze O?2 dismutation at a comparable rate to that of the 2:1 complex, or that the stability constant of the last species is much higher than that determined earlier by Kimura el al.,1 and only the 2:1 species is present in the solutions. With the indirect methods of cytochrome c and NBT for determining the ability of these complexes to catalyze O?2 dismutation, these compounds exhibited a much lower SOD activity. and kcat was determined to be (5.0 ± 0.3) × 106 and (7.± 0.4) × 101 M?1s?1. respectively using the two assays.  相似文献   

14.
A. Yokota  S. Kitaoka  K. Miura  A. Wadano 《Planta》1985,165(1):59-67
The nonenzymatic reaction of glyoxylate and H2O2 was measured under physiological conditions of the pH and concentrations of reactants. The reaction of glyoxylate and H2O2 was secondorder, with a rate constant of 2.27 l mol-1 s-1 at pH 8.0 and 25° C. The rate constant increased by 4.4 times in the presence of Zn2+ and doubled at 35°C. We propose a mechanism for the reaction between glyoxylate and H2O2. From a comparison of the rates of H2O2 decomposition by catalase and the reaction with glyoxylate, we conclude that H2O2 produced during glycolate oxidation in peroxisomes is decomposed by catalase but not by the reaction with glyoxylate, and that photorespiratory CO2 originates from glycine, but not from glyoxylate, in C3 plants. Simulation using the above rate constant and reported kinetic parameters leads to the same conclusion, and also makes it clear that alanine is a satisfactory amino donor in the conversion of glyoxylate to glycine. Some serine might be decomposed to give glycine and methylene-tetrahydrofolate; the latter is ultimately oxidized to CO2. In the simulation of the glycolate pathway of Euglena, the rate constant was high enough to ensure the decarboxylation of glyoxylate by H2O2 to produce photorespiratory CO2 during the glycolate metabolism of this organism.Abbreviations Chl chlorophyll - GGT glutamate: glyoxylate aminotransferase (EC 2.6.1.4) - Hepes 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid - SGT serine: glyoxylate aminotransferase (EC 2.6.1.45) This is the ninth in a series on the metabolism of glycolate in Euglena gracilis. The eighth is Yokota et al. (1982)  相似文献   

15.
Sheath blight (ShB) severely threatens rice cultivation and production; however, the molecular mechanism of rice defence against ShB remains unclear. Screening of transposon Ds insertion mutants identified that Calcineurin B-like protein-interacting protein kinase 31 (CIPK31) mutants were more susceptible to ShB, while CIPK31 overexpressors (OX) were less susceptible. Sequence analysis indicated two haplotypes of CIPK31: Hap_1, with significantly higher CIPK31 expression, was less sensitive to ShB than the Hap_2 lines. Further analyses showed that the NAF domain of CIPK31 interacted with the EF-hand motif of respiratory burst oxidase homologue (RBOHA) to inhibit RBOHA-induced H2O2 production, and RBOHA RNAi plants were more susceptible to ShB. These data suggested that the CIPK31-mediated increase in resistance is not associated with RBOHA. Interestingly, the study also found that CIPK31 interacted with catalase C (CatC); cipk31 mutants accumulated less H2O2 while CIPK31 OX accumulated more H2O2 compared to the wild-type control. Further analysis showed the interaction of the catalase domain of CatC with the NAF domain of CIPK31 by which CIPK31 inhibits CatC activity to accumulate more H2O2.  相似文献   

16.
A comparative kinetic study of extracellular catalases produced by Penicillium piceum F-648 and their variants adapted to H2O2 was performed in culture liquid filtrates. The specific activity of catalase, the maximum rate of catalase-induced H2O2 degradation (V max), V max/K M ratio, and the catalase inactivation rate constant in the enzymatic reaction (k in, s–1) were estimated in phosphate buffer (pH 7.4) at 30°C. The effective constant representing the rate of catalase thermal inactivation (k in *, s–1) was determined at 45°C. In all samples, the specific activity and K M for catalase were maximum at a protein concentration in culture liquid filtrates of (2.5–3.5) × 10–4 mg/ml. The effective constants describing the rate of H2O2 degradation (k, s–1) were similar to that observed in the initial culture. These values reflected a twofold decrease in catalase activity in culture liquid filtrates. We hypothesized that culture liquid filtrates contain two isoforms of extracellular catalase characterized by different activities and affinities for H2O2. Catalases from variants 5 and 3 with high and low affinities for H2O2, respectively, had a greater operational stability than the enzyme from the initial culture. The method of adaptive selection for H2O2 can be used to obtain fungal variants producing extracellular catalases with improved properties.  相似文献   

17.
Detoxification of hydrogen peroxide is a fundamental aspect of the cellular antioxidant responses in which catalases play a major role. Two differentially regulated catalase genes, catA and catB, have been studied in Aspergillus nidulans. Here we have characterized a third catalase gene, designated catC, which predicts a 475-amino-acid polypeptide containing a peroxisome-targeting signal. With a molecular mass of 54 kDa, CatC shows high similarity to other small-subunit monofunctional catalases and is most closely related to catalases from other fungi, Archaea, and animals. In contrast, the CatA (approximately 84 kDa) and CatB (approximately 79 kDa) enzymes belong to a family of large-subunit catalases, constituting a unique fungal and bacterial group. The catC gene displayed a relatively constant pattern of expression, not being induced by oxidative or other types of stress. Targeted disruption of catC eliminated a constitutive catalase activity not detected previously in zymogram gels. However, a catalase activity detected in catA catB mutant strains during late stationary phase was still present in catC and catABC null mutants, thus demonstrating the presence of a fourth catalase, here named catalase D (CatD). Neither catC nor catABC triple mutants showed any developmental defect, and both mutants grew as well as wild-type strains in H(2)O(2)-generating substrates, such as fatty acids, and/or purines as the sole carbon and nitrogen sources, respectively. CatD activity was induced during late stationary phase by glucose starvation, high temperature, and, to a lesser extent, H(2)O(2) treatment. The existence of at least four differentially regulated catalases indicates a large and regulated capability for H(2)O(2) detoxification in filamentous fungi.  相似文献   

18.
Here we examined whether Ca2+/Calmodulin (CaM) is involved in abscisic acid (ABA)-induced antioxidant defense and the possible relationship between CaM and H2O2 in ABA signaling in leaves of maize (Zea mays L.) plants exposed to water stress. An ABA-deficient mutant vp5 and its wild type were used for the experimentation. We found that water stress enhanced significantly the contents of CaM and H2O2, and the activities of chloroplastic and cytosolic superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR), and the gene expressions of the CaM1, cAPX, GR1 and SOD4 in leaves of wild-type maize. However, the increases mentioned above were almost arrested in vp5 plants and in the wild-type plants pretreated with ABA biosynthesis inhibitor tungstate (T), suggesting that ABA is required for water stress-induced H2O2 production, the enhancement of CaM content and antioxidant defense. Besides, we showed that the up-regulation of water stress-induced antioxidant defense was almost completely blocked by pretreatment with Ca2+ inhibitors, CaM antagonists and reactive oxygen (ROS) manipulators. Moreover, the analysis of time course of CaM and H2O2 production under water stress showed that the increase in CaM content preceded that of H2O2. These results suggested that Ca2+/CaM and H2O2 were involved in the ABA-induced antioxidant defense under water stress, and the increases of Ca2+/CaM contents triggered H2O2 production, which inversely affected the contents of CaM. Thus, a cross-talk between Ca2+/CaM and H2O2 may play a pivotal role in the ABA signaling.  相似文献   

19.
The role of H2O2 in abscisic acid (ABA)-induced NH4+ accumulation in rice leaves was investigated. ABA treatment resulted in an accumulation of NH4+ in rice leaves, which was preceded by a decrease in the activity of glutamine synthetase (GS) and an increase in the specific activities of protease and phenylalanine ammonia-lyase (PAL). GS, PAL, and protease seem to be the enzymes responsible for the accumulation of NH4+ in ABA-treated rice leaves. Dimethylthiourea (DMTU), a chemical trap for H2O2, was observed to be effective in inhibiting ABA-induced accumulation of NH4+ in rice leaves. Inhibitors of NADPH oxidase, diphenyleneiodonium chloride (DPI) and imidazole (IMD), and nitric oxide donor (N-tert-butyl-α-phenylnitrone, PBN), which have previously been shown to prevent ABA-induced increase in H2O2 contents in rice leaves, inhibited ABA-induced increase in the content of NH4+. Similarly, the changes of enzymes responsible for NH4+ accumulation induced by ABA were observed to be inhibited by DMTU, DPI, IMD, and PBN. Exogenous application of H2O2 was found to increase NH4+ content, decrease GS activity, and increase protease and PAL-specific activities in rice leaves. Our results suggest that H2O2 is involved in ABA-induced NH4+ accumulation in rice leaves.  相似文献   

20.
A biocatalatic pathway involving chromogenic probe has been proposed for the determination of catalase activity by means of iso-nicotinicacidhydrazide (INH) and pyrocatechol (PC). The assay is based on the enzymatic consumption of hydrogen peroxide using INH-PC system. The response of the catalase activity was ascertained by the rate of the reaction involving 14.10 mM H2O2. On addition of H2O2, INH-PC indicator system formed a chromogenic product with absorbance maxima at 490 nm. Hence the activity of catalase was directly measured by the chromogenic response in the formation of the coupled product. The catalase assay was elaborated by the kinetic response of the INH-PC system. The linearity of the catalase activity and H2O2 was in the range 0.2-7.0 units and 1.76-7.0 mM, respectively in 3 ml solution. The catalytic efficiency and catalytic power were calculated. The Michaelis-Menten constant of INH, PC and H2O2 were found to be 0.344, 0.176 and 8.82 mM, respectively. The indicator reaction was applied in the determination of catalase activity in mycelia mats and culture media.  相似文献   

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