Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence on diaminobenzidine staining of four variables: prefixation in aldehyde, temperature and pH of incubation, and H2O2 concentration, was investigated in catalase-, as well as in peroxydase-containing material. Catalase from five different sources and five types of peroxidase were examined. It is concluded: (a) when cells are incubated without prior fixation, in a DAB medium at room temperature and pH 7.3 with 0.003% H2O2, peroxidases produce a visible cytochemical stain, while catalases do not; (b) the cytochemical reaction elicited by catalases is stimulated by prior aldehyde fixation in specified conditions, and incubation at 45 degrees C and pH 9.7 with 0.06% H2O2; (c) under the latter circumstances several peroxidases also stain. Ultrastructural preservation is satisfactory in tissues incubated prior to fixation.
 ...
PMID:Cytochemical discrimination between catalases and peroxidases using diaminobenzidine. 23 53

This coupled-enzyme method for determining the activity of catalase (EC 1.11.1.6) in erythrocyte lysates is based on measuring the absorbance at 340 nm of NADH produced from the peroxidic reaction between ethanol, hydrogen peroxide, and catalase. Hydrogen peroxide is produced as a substrate in situ from the oxidation of glucose catalyzed by glucose oxidase (EC 1.1.3.4). Catalase oxidizes ethanol to acetaldehyde in the presence of hydrogen peroxide. Acetaldehyde is then oxidized by aldehyde dehydrogenase (EC 1.2.1.5) to produce acetate with concomitant conversion of NAD+ to NADH. The reaction did not follow strict zero-order kinetics; enzyme activity was quantified by using initial rates and standards prepared from purified catalase. The method demonstrated within-run and between-run CVs of 1.0% to 2.9% and 2.4% to 3.3%, respectively. This semiautomated method correlated well (r = 0.92) with the more tedious manual method involving measurement at 240 nm.
 ...
PMID:Coupled-enzyme determination of catalase activity in erythrocytes. 237 48

A growing body of experimental data indicates that reactive oxygen metabolites such as superoxide, hydrogen peroxide, and hydroxyl radical may mediate the mucosal injury produced by reperfusion of ischemic intestine. Xanthine oxidase has been proposed as the primary source of these reduced O2 species because pretreatment with xanthine oxidase inhibitors such as allopurinol or pterin aldehyde prevent postischemic mucosal injury. Another potential source of oxygen radicals is the inflammatory neutrophil. To ascertain whether neutrophils could play a role in the pathogenesis of ischemia-reperfusion injury in the small bowel we examined the effect of ischemia and reperfusion on neutrophil infiltration and tissue levels of reduced glutathione, superoxide dismutase, and catalase. Our studies demonstrate that reperfusion of ischemic intestines results in a dramatic increase (1,800%) in neutrophil infiltration and a concurrent loss of reduced glutathione and superoxide dismutase of 60 and 30%, respectively. Catalase activity was unaffected by ischemia-reperfusion. Pretreatment with allopurinol or administration of superoxide dismutase prevented the influx of neutrophils and retarded the drop in reduced glutathione levels. These results suggest a relationship among xanthine oxidase-generated oxy radicals, neutrophil extravasation, and mucosal damage. We propose that ischemia and reperfusion results in xanthine oxidase-generated, superoxide-dependent accumulation of inflammatory neutrophils in the mucosa where neutrophil-derived reactive oxygen metabolites mediate and/or exacerbate intestinal injury.
 ...
PMID:Xanthine oxidase and neutrophil infiltration in intestinal ischemia. 302 Sep 94

Xanthine oxidase with acetaldehyde as substrate (the XOA system) generated superoxide anion and hydrogen peroxide, but this system had only weak bactericidal activity. Addition of Fe2+ and EDTA to the XOA system (XOA-Fe-EDTA system) increased bactericidal activity against Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Salmonella typhimurium, although both Mycobacterium tuberculosis and Candida albicans remained highly resistant. Catalase (H2O2 scavenger) and mannitol (.OH scavenger) almost completely inhibited the bactericidal activity of the XOA-Fe-EDTA system whereas SOD (O2- scavenger) was less inhibitory. Azide (1O2 scavenger) caused no such inhibition. The results suggest the possible role of .OH, H2O2 and O2- in the XOA-Fe-EDTA-mediated antimicrobial system, as effector molecules. There was no correlation between resistance of a given bacterium to active oxygen and the level of endogenous active oxygen-scavengers.
 ...
PMID:Susceptibility of micro-organisms to active oxygen species: sensitivity to the xanthine-oxidase-mediated antimicrobial system. 312 35

Catalase activity in blood collected from young rats naive to ethanol (65 days) was significantly and positively correlated with later voluntary consumption of ethanol. Catalase activity levels were also correlated with catalase activity in brain and blood sampled after exposure to ethanol. The results obtained in the present study extend and confirm earlier findings (Aragon et al. 1985c) that brain catalase activity and voluntary ethanol intake are unidirectionally and causally related. The results also suggest that brain catalase activity may be part of an enzymatic system controlling the production and elimination of acetaldehyde in brain. This system may be a biological marker system mediating the affinity of organisms to ingest ethanol.
 ...
PMID:Catalase activity measured in rats naive to ethanol correlates with later voluntary ethanol consumption: possible evidence for a biological marker system of ethanol intake. 314 22

The primary structure of the mitochondrial form of horse liver aldehyde dehydrogenase has been determined, utilizing peptide analyses and homology with other enzyme forms. The subunit exhibits N-terminal heterogeneity in size similar to that for the corresponding human mitochondrial protein, the longest form having 500 residues. Catalase was identified as a contaminant of the preparations. All four pairs within a set of aldehyde dehydrogenases can now be compared, including the same two species variants (horse and human) for both the cytosolic and mitochondrial enzyme, revealing characteristic differences although Cys-302 and other segments of presumed functional importance are unchanged. The cytosolic and mitochondrial enzymes are clearly different (172 exchanges in the horse pair; 160 exchanges in the human pair) and the mitochondrial forms are more conserved (28 exchanges of 500 residues) than the cytosolic ones (43 exchanges). Distributions of the residue substitutions also differ between the two enzyme types. These results suggest a comparatively distant separation of the cytosolic and mitochondrial enzymes into forms with separate functional constraints that are more strict on the mitochondrial than the cytosolic enzyme. Unexpectedly, positions with residues unique to one of the four enzymes are about twice as common in both of the horse proteins than in either of the human proteins. This difference may reflect a general pattern for human/non-human proteins, showing that not only functional properties of the protein, but also other factors, such as generation time (longer in man than in horse), are important for enzyme divergence.
 ...
PMID:Mitochondrial aldehyde dehydrogenase from horse liver. Correlations of the same species variants for both the cytosolic and the mitochondrial forms of an enzyme. 335 12

The gluconic fragment of strophantin K oxidation by sodium metaperiodate yields a dialdehyde derivate conjugated with catalase. The conjugate obtained contains 11 molecules of cardiac glucoside. Adsorption and circular dichroism spectra of the native enzyme and its conjugate were compared and structural differences between both samples were revealed. The kinetics of ethanol oxidation into acetaldehyde by cumene hydroperoxide was studied at 30 degrees C in the phosphate buffer pH 6.6; this reaction was shown to proceed with the participation of catalase and its cat-str conjugate. The catalytic constants for catalase are 1.2-1.5 times as high as those for cat-str, whereas the Km values for both substrates for the conjugate as 1.5-2 times as high as those for catalase. Catalase modification by strophantin K increases the enzyme thermostability up to the isokinetic point of 40 degrees C; above this threshold the cat-str thermostability decreases as compared with the native enzyme. The thermodynamical activation parameters for catalase and cat-str inactivation were determined.
 ...
PMID:[Kinetic properties of catalase and its conjugates with strophanthin K in ethanol oxidation by cumyl hydroperoxide]. 376 32

Methanol and ethanol were rapidly metabolized to formaldehyde and acetaldehyde in the presence of ascorbate, 1,10-phenanthroline and either guinea pig hepatic 100,000 g supernatant or 12,000 g pellet fractions. The specific activity of methanol oxidation was 1720 nmoles formaldehyde formed/min/mg protein in the 100,000 g fraction and 790 in the 12,000 g pellet fraction. The specific activity of ethanol oxidation was 1590 nmoles acetaldehyde formed/min/mg protein in the 100,000 g fraction and 820 in the 12,000 g pellet fraction. The activity was enzymatic in that it was linear with time, proportional to protein concentration, and sensitive to temperature. Catalase appeared to be the enzymatic component responsible for the oxidation. In this ascorbate-dependent alcohol oxidation system, oxygen was consumed and H2O2 was formed. When purified catalase and ascorbate were used, complex I was detected and methanol was oxidized.
 ...
PMID:Ascorbic acid and alcohol oxidation. 650 46

The process of hydrogen peroxide continuous decomposition by the preparation of the fungus Penicillium vitale catalase immobilized by aminoorganosilica which were activated by glutaric aldehyde, cyanuric chloride or 2,4-toluylene diisocyanate. Catalase with an oxidized carbohydrate component was used as well. Such a modified enzyme was directly bound with the surface of aminocontaining silica and alumina. It is shown that in the process of H2O2 decomposition the preparations of immobilized catalase are inactivated. The decrease in its activity is described by a model which suggests that rates of hydrogen peroxide decomposition and enzyme inactivation are described by the first order equations. A method for calculation and prediction of mean time of continuous operation of columns with bound catalase and other immobilized enzymes is suggested in terms of the given model.
 ...
PMID:[Stability of Penicillium vitale immobilized catalase in continuous decomposition of hydrogen peroxide]. 728 Dec 55

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a potent tobacco-specific carcinogen, has been demonstrated to induce lung tumors in animals and is suspected to be a human carcinogen. Cytochromes P450 are the major enzymes responsible for the activation of NNK in microsomes from the lung and liver of rat and mouse, as well as human liver. The present study investigated the enzymes responsible for the metabolic activation of NNK in human lung microsomes. In the presence of a NADPH-generating system, the formation of keto aldehyde and keto alcohol (alpha-hydroxylation products, measured together), keto acid, hydroxy acid, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol was observed in human lung microsomes. Carbon monoxide (90%) decreased the rate of NNK oxidation by 5-49%, depending on the human lung microsomal samples analyzed. Coumarin decreased the oxidation of NNK by 9-34%, and an antibody against human P450 2A6 decreased the metabolism of NNK by 8-37%, suggesting the involvement of P450 2A6 in NNK oxidation. alpha-Napthoflavone inhibited NNK oxidation by 6-26%, possibly due to the inhibition of P450 1A1. P450 1A1-expressed microsomes catalyzed the formation of keto aldehyde and keto alcohol, exhibiting Km values of 1400 microM and 371 microM, respectively. In the absence of NADPH, NNK metabolism resulted in the formation of keto acid, keto aldehyde, and keto alcohol, and the activities in different lung samples were decreased by indomethacin (100 microM; cyclooxygenase inhibitor) or nordihydroguaiaretic acid (100 microM; lipoxygenase inhibitor) by 0-27% or 30-66%, respectively. The addition of arachidonic acid (10-100 microM) increased the rate of the formation of keto aldehyde and keto alcohol approximately 2-fold but inhibited the formation of keto acid. Soybean lipoxygenase increased the rate of formation of keto aldehyde and keto alcohol in a concentration-dependent manner. The increased rate in NNK oxidation by arachidonic acid or lipoxygenase was inhibited completely by nordihydroguaiaretic acid. Catalase, thiourea, and conjugated linoleic acid decreased the rate of NNK oxidation by 47, 20, and 45%, respectively. tert-Butyl-hydroperoxide, cumene hydroperoxide, and hydrogen peroxide increased the rate of formation of keto aldehyde and keto alcohol by 210, 40, and 50%, respectively. The results suggest that P450 enzymes are only partially responsible for the activation of NNK in human lung microsomes, and P450 2A6 or a P450 2A6-related enzyme seems to be involved in the activation. Furthermore, lipoxygenase and lipid hydroxperoxides may play important roles in the oxidation of NNK in human lung microsomes.
 ...
PMID:Activation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in human lung microsomes by cytochromes P450, lipoxygenase, and hydroperoxides. 758 36


1 2 3 Next >>