Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.6 (catalase)
 55,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies were performed to determine the effects of iron deficiency on brain metabolism in rats. Concentrations of cytochrome pigments, oxidative phosphorylation, and catalase and monoamine oxidase activities in brain tissue were unaffected by iron deficiency. However, activities of aldehyde oxidase, a key enzyme in the pathway of serotonin degradation, were significantly reduced, and concentrations of serotonin and total 5-hydroxyindole compounds were elevated in brain tissue of iron-deficient animals. Aldehyde oxidase activities and concentrations of 5-hydroxyindole compounds in brain tissues returned to approximately normal values one week after treatment of iron deficient animals with iron dextran.
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PMID:Iron deficiency in the rat: biochemical studies of brain metabolism. 64 92

Differences in the absorption spectrum of the Penicillum vitale catalase in the visible region as compared to the absorption spectrum for catalase of animal origin are established to be due to the prosthetic group of the enzyme. A molecule of P. vitale catalase is determined to contain 0.051 +/- 0.0003% of iron. It corresponds to two iron atoms per enzyme molecule and to a twice as low content of iron as in a molecule of the bovine liver catalase. An assumption is advanced that the P. vitale catalase contains two hemin groups located in two protein subunits.
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PMID:[Spectral properties of the prosthetic group of Penicillium vitale catalase]. 66 35

Arachidonic acid (AA) is the essential substrate for production of platelet endoperoxides and thromboxanes. Iron or heme is an essential cofactor for the peroxidase, lipoxygenase and cyclo-oxygenase enzymes involved in formation of these products. The present study has examined the direct interactions between iron and arachidonic acid. Iron caused the oxidation of AA into more polar products which could be detected by UV absorbtion at 232 nM or the thiobarbituric acid (TBA) reaction. High pressure liquid chromatography, chem-ionization and electron-impact mass spectrometry and nuclear magnetic resonance spectroscopy suggest that the major product was a hydroperoxide of AA. Ferrous iron (Fe++) and oxygen were absolute requirements. Fe++ was converted to the ferric iron (Fe+++) state during oxidation of AA, but Fe+++ could not substitute for Fe++. No other enzymes, cofactors or ions were involved. Conversion of AA to a hydroperoxide by Fe++ was inhibited by the antioxidant, 2, (3)-Tert-butyl-4-hydroxyanisole, the radical scavenger, nitroblue tetrazolium, and iron chelating agents, including EDTA, imidazole and dihydroxybenzoic acid. The reaction was not affected by superoxide dismutase, catalase or aspirin. These findings and preliminary studies of the Fe++ induced oxidation product of AA as a substrate for prostaglandin synthesis and inhibitor of prostacyclin production indicate the critical role of Fe++ in AA activation.
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PMID:The role of iron in prostaglandin synthesis: ferrous iron mediated oxidation of arachidonic acid. 71 48

The oxidation of arachidonic acid by ferrous sulfate provides a useful model to study the role of iron in lipid oxidation reactions. We have employed nitroblue tetrazolium (NBT) in the present investigation to evaluate the mechanism of this reaction. In the presence of arachidonic acid, Fe +++, and O2, the yellow dye NBT was rapidly reduced to the blue form, NBTH2. The molar ratio of arachidonic acid to Fe++ in this rapid reaction was 1:1, showing an interaction of one fatty acid molecule per iron molecule. Approximately one molecule of NBT was reduced per four molecules of arachidonic acid and Fe++. Reduction of NBT was accompanied by oxidation of Fe++ to Fe+++, suggesting the transfer of four electrons from the Fe++ to NBT to reduce the dye. Arachidonic acid was found to be unchanged when extracted at the end of the reaction, indicating formation of a complex that could dissociate leaving intact arachidonic acid. Evidence for the presence of such a complex which slowly dissociates during the reaction was obtained after longer incubations with small amounts of arachidonic acid. NBT reduction was not inhibited by agents which hydrolyze superoxide, by catalase or by agents which trap hydroxy radicals. We, therefore, propose a model in which NBT traps a radical generated on the arachidonic acid molecule. The proposed model suggests mechanisms for other fatty acid oxidation reactions such as prostaglandin and hydroperoxy fatty acid synthesis.
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PMID:Ferrous iron mediated oxidation of arachidonic acid: studies employing nitroblue tetrazolium (NBT). 71 68

Rat kidney homogenates, in phosphate-EDTA buffer, consistently catalyzed the formation of T3 from added L-thyroxine (T4). The formation of T3 was assessed by both paper chromatography and RIA of T3. Conversion of T4 to T3 appeared to be enzymatic, showing pH and temperature optima (pH 7.0 and 37 C, respectively) and tissue and time dependence. Formation of T3 was unaffected by azide, cyanide, or catalase, nor was it dependent upon oxygen; indeed, under anaerobic conditions conversion of T4 to T3 was enhanced. Dialyzed homogenate retained full activity, and no cofactor requirement was demonstrated. A role of iron and thiol groups in the enzymatic formation of T3 from T4 was suggested by the inhibitory action of iron chelators and thiol-blocking reagents. The capacity of kidney for T3 formation was considerable and increased with increasing T4 concentrations, being approximately 2 nmol/g tissue/h at very high T4 levels. The apparent Km was estimated to be 3 x 10(-6) M. The conversion of T4 to T3 was inhibited by propylthiouracil at micromolar concentrations whereas methimazole, iodide, and lithium salts were without effect. The enzymatic activity of the homogenates was associated with its particulate components, the readily sedimenting fractions corresponding to plasma membranes and mitochondria being most active, and was absent from nuclei and cytosol.
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PMID:Conversion of L-thyroxine to triiodothyronine in rat kidney homogenate. 74 83

A patient with a cerebro-hepato-renal syndrome was investigated. The visceral manifestations were those of the Zellweger syndrome (ZS); however, the child exhibited muscular hypertonia and survived into the 2nd year of life. Ultramicroscopically, hepatocytes were lacking peroxisomes, but, contrary to findings in one patient with ZS [2], contained smooth endoplasmic reticulum. No catalase was found by histochemistry or spectroscopy. Mitochondria showed normal succinate and glutamate respiration, and normal coupling of respiration to the phosphorylation potential. The cytochrome (cyt) content was diminished to one-third with an abnormally inversed redox pattern of the respiratory chain in the controlled state, cyt b being 5%, cyt c 23% reduced. The oxygen affinity of cyt a3 was normal. These findings exclude a defect in the nonheme iron protein region of the respiratory chain as described in ZS [2], but point to a functional abnormality of cyt b in out patient.
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PMID:A metabolic disorder similar to Zellweger syndrome with hepatic acatalasia and absence of peroxisomes, altered content and redox state of cytochromes, and infantile cirrhosis with hemosiderosis. 84 60

A mutant of the yeast Pichia guilliermondii was produced by means of UV; the mutant was capable of riboflavin overproduction in the presence of high concentrations of iron in the medium. The content of total and non-hemin iron and cytochrome c, and the activity of catalase, were lower in the cells of the mutant than in the parent cells, while the activity of riboflavin synthetase was higher. The content of iron in the cells increased when the mutant was cultivated on media with citric acid, siderochromes of Klebsiella aerogenes, Neurospora crassa, Rhodotorula glutinis, cultural broth of Pichia ohmeri, and autolysate of brewer's yeast, whereas the flavinogenous activity of the cells decreased. Rotenone inhibited respiration of the intact cells of the mutant producing elevated amounts of riboflavin; therefore, flavinogenesis was not regulated by non-hemin iron on the first segment of the respiratory chain. Overproduction of riboflavin in the mutant of Pichia guilliermondii was proved to be a recessive property.
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PMID:[A flavinogenic mutant of the yeast Pichia guilliermondii with impaired iron transport]. 93 79

The effect of high-spin heme iron in beef liver catalase on the longitudinal and transverse proton relaxation rates of the solvent has been used to probe the environment of the paramagnetic center. The longitudinal proton relaxation rates were measured as a function of temperature (5-31 degrees C), frequency (5-100 MHz), and pH. T1p was found to be pH independent in the range 6-11, indicating that no significant difference occurs in the heme surrounding within this pH range. The ligands formate and acetate, which preserve the spin state of the heme iron upon ligation, displace a water molecule from the sixth coordination position. This reaction is pH independent, while the binding measured by optical spectroscopy is pH dependent. The electron methanol and ethanol essentially do not change the proton relaxation rates. The temperature and frequency dependencies indicate that the relaxation times are governed by the electronic relaxation time of the high-spin ferric iron tau s. Tau s, which was found to be frequency independent, could not be determined from the T1p/T2p ratio, but only from the frequency dependence of the longitudinal relaxation rate at low frequencies. The results of the least-squares fit of the data to the theory indicate that there is one iron-bound rapidly exchanging water molecule. For the Fe3+ ion it was determined that tau s = 7 x 10(-11) s.
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PMID:A nuclear magnetic resonance study of the heme environment in beef liver catalase. 94 45

Resonance Raman spectra of oxidized hydroperoxidases are examined for shifts in the structure-sensitive, anomalously polarized bands; these are found, respectively, at 1576, 1567 and 1570 cm-1 in the high-spin resting enzymes: horse radish peroxidase, horse blood catalase, and cytochrome c peroxidase. In compound II of horse radish peroxidase and horse blood catalase, and in the enzyme-substrate complex of cytochrome c peroxidase, this band appears at 1587-1590 cm-1 and indicates the iron atom is now in-plane with the porphyrin ring. Weak Raman scattering found with horse radish peroxidase I is consistant with a porphyrin eta-cation radical formulation.
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PMID:Laser Raman spectra of oxidized hydroperoxidases. 94 50

A green iron-chlorin protein was purified 160-fold from a lyophilized extract of Aspergillus niger by ion-exchange chromatography and gel filtration with a yield of 25%. The purified preparation appeared nearly homogeneous on sedimentation analysis and the sedimentation coefficient of the protein at infinite dilution was 13.4S. Its molecular weight was calculated to be 2.8--3.2 X 10(5) from sedimentation and gel filtration data. The ferric form of the protein had absorption maxima at 587.5 and 708 nm in the visible region and a Soret band at 404 nm. High-spin ESR signals of a rhombically distorted ferric iron-chlorin complex were observed at g = 6.5 and 5.3 together with unidentified, weaker signals at g = 4.3 and 2.0. The ferric form reacted readily with cyanide to give a complex showing absorption peaks at 422 and 632 nm and a shoulder at about 595 nm. When the protein combined with cyanide its high-spin ESR signals disappeared and low-spin signals at g = 1.88, 2.29, anous form having absorption maxima at 622 and about 410 nm. The rate of reduction by dithionite was slightly reduced by the presence of either nitrite or sulfite, and greatly accelerated by the presence of hydroxylamine. The reduced spectrum obtained in the presence of hydroxylamine had maxima at 620 and about 420 nm. The ferric cyanide complex did not show any spectral change on addition of dithionite. The green prosthetic group could be extracted with acidified acetone and the absorption maxima of the pyridine ferrihemochrome were at 413 and 599 nm. On removal of metal from the prosthetic group the characteristic spectrum of a chlorin was obtained. The absorption maxima of a solution of the chlorin in benzene were at 403, 501, 537, 576, 595, and 655 nm, the 655 nm band being strongest of those in the visible region. No significant amount of flavin was detected in the purified preparation. The iron-chlorin protein catalyzed methyl viologen-linked reduction of hydroxylamine and also that of nitrite at a slower rate under the same conditions, but not evidence that it reduced sulfite was obtained in the present study. The purified preparation also had high catalase [ec 1.11.1.6] activity. Crystalline material was obtained by gradual concentration of the purified preparation at about pH 6.
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PMID:Isolation, properties, and crystallization of an iron-chlorin protein from Aspergillus niger. 97 55


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