Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It was possible to quantitate the tetramethyl-p-phenylenediamine (TMPD) oxidase reaction in Azotobacter vinelandii strain O using turbidimetrically standarized resting cell suspensions. The Q(O2) value obtained for whole cell oxidation of ascorbate-TMPD appeared to reflect the full measure of the high respiratory oxidative capability usually exhibited by this genera of organisms. The Q(O2) value for the TMPD oxidase reaction ranged from 1,700 to 2,000 and this value was equivalent to that obtained for the oxidation of the growth substrate, e.g., acetate. The kinetic analyses for TMPD oxidation by whole cells was similar to that obtained for the "particulate" A. vinelandii electron transport particle, that fraction which TMPD oxidase activity is exclusively associated with. Under the conditions used, there appeared to be no permeability problems; TMPD (reduced by ascorbate) readily penetrated the cell and oxidized at a rate comparable to that of the growth substrate. This, however, was not true for the oxidation of another electron donor, 2,6-dichloroindophenol, whose whole cell Q(O2) values, under comparable conditions, were twofold lower. The TMPD oxidase activity in A. vinelandii whole cells was found to be affected by the physiological growth conditions, and resting cells obtained from cells grown on sucrose, either under nitrogen-fixing conditions or on nitrate as the combined nitrogen source, exhibited low TMPD oxidase rates. Such low TMPD oxidase rates were also noted for chemically induced pleomorphic A. vinelandii cells, which suggests that modified growth conditions can (i) alter the nature of the intracellular terminal oxidase formed (or induced), or (ii) alter surface permeability, depending upon the growth conditions used. Preliminary studies on the quantitative TMPD oxidation reaction in mutant whole cells of both Azotobacter and a well-known Mucor bacilliformis strain AY1, deficient in cytochrome oxidase activity, showed this assay can be very useful for detecting respiratory deficiencies in the metabolism of whole cells.
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PMID:Tetramethyl-p-phenylenediamine oxidase reaction in Azotobacter vinelandii. 17 91

1. The magnitude of the protonmotive force in respiring bovine heart submitochondrial particles was estimated. The membrane-potential component was determined from the uptake of S14CN-ions, and the pH-gradient component from the uptake of [14C]methylamine. In each case a flow-dialysis technique was used to monitor uptake. 2. With NADH as substrate the membrane potential was approx. 145mV and the pH gradient was between 0 and 0.5 unit when the particles were suspended in a Pi/Tris reaction medium. The addition of the permeant NO3-ion decreased the membrane potential with a corresponding increase in the pH gradient. In a medium containing 200mM-sucrose, 50mM-KCl and Hepes as buffer, the total protonmotive force was 185mV, comprising a membrane potential of 90mV and a pH gradient of 1.6 units. Thus the protonmotive force was slightly larger in the high-osmolarity medium. 3. The phosphorylation potential (= deltaG0' + RT ln[ATP]/[ADP][Pi]) was approx. 43.1 kJ/mol (10.3kcal/mol) in all the reaction media tested. Comparison of this value with the protonmotive force indicates that more than 2 and up to 3 protons must be moved across the membrane for each molecule of ATP synthesized by a chemiosmotic mechanism. 4. Succinate generated both a protonmotive force and a phosphorylation potential that were of similar magnitude to those observed with NADH as substrate. 5. Although oxidation of NADH supports a rate of ATP synthesis that is approximately twice that observed with succinate, respiration with either of these substrates generated a very similar protonmotive force. Thus there seemed to be no strict relation between the size of the protonmotive force and the phosphorylation rate. 6. In the presence of antimycin and/or 2-n-heptyl-4-hydroxyquinoline N-oxide, ascorbate oxidation with either NNN'N'-tetramethyl-p-phenylenediamine or 2,3,5,6-tetramethyl-p-phenylenediamine as electron mediator generated a membrane potential of approx. 90mV, but no pH gradient was detected, even in the presence of NO3-. These data are discussed with reference to the proposal that cytochrome oxidase contains a proton pump.
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PMID:The protonmotive force in bovine heart submitochondrial particles. Magnitude, sites of generation and comparison with the phosphorylation potential. 21 21

The effects of cyanide, thiocyanide, azide, nitrite, nitrate, ferricyanide, persulfate, sulfide and halogenides on the intensities of the EPR spectrum and the band of 825 nm of cardiac cutochrome oxidase were studied. It was shown that according to their action on the copper the anions may be classified into three groups: 1) anions inducing the reduction of the copper (CN-, CNS-, S2-) anions changing the environment of the copper (N3-, NO2-); 3) anions slightly interacting with the copper (NO3-, halogenides). The incubation of cytochrome oxidase with ferricyanide led to the formation of a free-radical component without causing any pronounced changes in the copper environment; however, treatment of the protein with persulfate was accompanied by an irreversible modification of the copper EPR spectrum.
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PMID:[Interaction of inorganic anions with copper atoms of cytochrome oxidase]. 22 57

During germination, Streptomyces antibioticus arthrospores passed through stages: darkening, swelling and germ tube emergence. The first stage, darkening, whose main features were a decrease in absorbance and a loss of refractility, only required exogenous divalent cations (Ca2+, Mg2+ or Fe2+) and energy that can be obtained from the spore reserves. This stage was blocked by agents that inhibit ATP formation but not by antibiotics that inhibit macromolecular synthesis. The second stage, swelling, needed an exogenous carbon source and was not blocked by mitomycin C. In this stage, the spores exhibited the highest cytochrome oxidase and catalase activities and respiratory quotient. The last stage, germ tube emergence, required additional carbon and nitrogen sources. Ammonium compounds were superior to nitrate. Dry weight remained constant during the stages of darkening and swelling, with a rapid increase from the moment of germ tube emergence. Optimum pH and temperature for germination were 8.0 and 45 degrees C, respectively. Heat treatment (55 degrees C for 10 min) had no effect on germination. The fine structure of the spore underwent important changes during germination. The wall of the swollen spore became stratified and the inner layer was continuous with the germ tube wall. Macromolecular synthesis occurred in the sequence RNA, protein and then DNA. Rifampicin, streptomycin and mitomycin C prevented synthesis when added at the start of incubation. The same effect was obtained if the addition was made during germination, except with mitomycin C which inhibited DNA, but not RNA and protein synthesis.
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PMID:Fine structure, physiology and biochemistry of arthrospore germination in Streptomyces antibioticus. 34 27

The study of the participation of metals in evolution of oxidation-reduction processes is subdivided into two periods. During the first of them, from 1897 to 1937, the significance of manganese, iron, titanium, molybdenum, vanadium and copper in most important processes of metabolism was discovered. The second period, from 1937 to 1977, was devoted to the study of the role of metals in individual representatives of oxidoreductases and their evolution during transition of organisms from anaerobiosis to aerobiosis. In this evolution of special importance were bimetallic enzymes, such as nitrogenase, some nitrate reductases and hydrogenases, carbon dioxide reductase, xanthine oxidase, cytochrome oxidase. Owing to their ability to accomplish conjugated oxidation-reduction reactions, these oxidoreductases were transitional to still more complicated polymetallic systems with whose participation the electron transfer chains in subcellular structures were formed.
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PMID:[Participation of polyvalent metals in the evolution of oxidoreductases]. 91 1

Pseudomonas AM1, Hyphomicrobium X and Pseudomonas MS all contain cytochrome a/a(3) and a b-type cytochrome able to react with CO. Pseudomonas AM1 and Hyphomicrobium X also have a CO-binding cytochrome c. The purified cytochrome c (redox potential 0.26V) of Pseudomonas AM1 was not susceptible to oxidation by molecular oxygen. CO reacted slowly with the reduced form giving a CO difference spectrum with a peak at 412nm and troughs at 420nm and 550nm. Similar results were obtained with the cytochrome c of Hyphomicrobium (aerobically grown or anaerobically grown with nitrate) and with that of Pseudomonas extorquens. The results given in the present paper are incompatible with an oxygenase or oxidase function for the soluble cytochrome c of methylotrophs. Studies with whole cells of Pseudomonas AM1 and a cytochrome c-deficient mutant have demonstrated that cytochrome b (redox potential 0.009V) is the first cytochrome in the electron-transport chain for oxidation of all substrates except methanol (and ethanol) whose oxidation does not involve this cytochrome. All substrates are usually oxidized by way of cytochrome c and cytochrome oxidase (cytochrome a/a(3)), but there is an alternative route for the reduction of cytochrome a/a(3) in the mutant lacking cytochrome c. Results of experiments on cyanide inhibition of respiration and cytochrome oxidation support the suggestion that the susceptibility of cytochrome b to oxidation by molecular oxygen (reflected in its ability to react with CO) is probably irrelevant to the normal physiology of Pseudomonas AM1.
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PMID:The microbial metabolism of C1 compounds. The electron-transport chain of Pseudomonas am1. 122 Jun 89

A comparative analysis of the phenotypic and serological properties of Carnobacterium strains associated with mortalities of cultured striped bass and channel catfish and the properties of isolates from wild brown bullhead catfish in the Chesapeake Bay area in Maryland was conducted. All of the strains were gram-positive, facultatively anaerobic, nonmotile, non-spore-forming rods occurring singly or in short chains. They did not produce cytochrome oxidase or catalase, did not reduce nitrate, failed to produce H2S, were unable to grow on acetate medium, and did not produce gas from glucose or gluconate. The temperature and salinity ranges for most of the strains were 10 to 37 degrees C and 0 to 6% NaCl, respectively. The strains all fermented mannitol and inulin and were arginine dihydrolase positive; these are typical characteristics of Carnobacterium piscicola. The carbohydrate fermentation pattern exhibited by all of the isolates with the API-50 CHL system was also very similar to that shown by C. piscicola. Acid was produced from ribose, glucose, fructose, mannose, mannitol, N-acetylglucosamine, amygdaline, arbutin, esculin, salicin, cellobiose, maltose, sucrose, trehalose, and gentiobiose. The Carnobacterium strains did not show proteolytic, lipolytic, amylolytic, or hemolytic activity. Eighteen drugs were tested; all strains proved to be resistant to chloramphenicol, gentamicin, kanamycin, streptomycin, trimethoprim, quinolones, and nitrofurans. The analysis of membrane proteins supported the phenotypic similarities, two main patterns were established, one shared by the striped bass isolates and the reference strain of C. piscicola and another shared by most of the catfish strains. However, the agglutination assays demonstrated that only one Carnobacterium strain from striped bass was serologically related to C. piscicola ATCC 35586.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biochemical and serological characterization of Carnobacterium spp. isolated from farmed and natural populations of striped bass and catfish. 178 76

Under anaerobic circumstances in the presence of nitrate Paracoccus denitrificans is able to denitrify. The properties of the reductases involved in nitrate reductase, nitrite reductase, nitric oxide reductase, and nitrous oxide reductase are described. For that purpose not only the properties of the enzymes of P. denitrificans are considered but also those from Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas stutzeri. Nitrate reductase consists of three subunits: the alpha subunit contains the molybdenum cofactor, the beta subunit contains the iron sulfur clusters, and the gamma subunit is a special cytochrome b. Nitrate is reduced at the cytoplasmic side of the membrane and evidence for the presence of a nitrate-nitrite antiporter is presented. Electron flow is from ubiquinol via the specific cytochrome b to the nitrate reductase. Nitrite reductase (which is identical to cytochrome cd1) and nitrous oxide reductase are periplasmic proteins. Nitric oxide reductase is a membrane-bound enzyme. The bc1 complex is involved in electron flow to these reductases and the whole reaction takes place at the periplasmic side of the membrane. It is now firmly established that NO is an obligatory intermediate between nitrite and nitrous oxide. Nitrous oxide reductase is a multi-copper protein. A large number of genes is involved in the acquisition of molybdenum and copper, the formation of the molybdenum cofactor, and the insertion of the metals. It is estimated that at least 40 genes are involved in the process of denitrification. The control of the expression of these genes in P. denitrificans is totally unknown. As an example of such complex regulatory systems the function of the fnr, narX, and narL gene products in the expression of nitrate reductase in E. coli is described. The control of the effects of oxygen on the reduction of nitrate, nitrite, and nitrous oxide are discussed. Oxygen inhibits reduction of nitrate by prevention of nitrate uptake in the cell. In the case of nitrite and nitrous oxide a competition between reductases and oxidases for a limited supply of electrons from primary dehydrogenases seems to play an important role. Under some circumstances NO formed from nitrite may inhibit oxidases, resulting in a redistribution of electron flow from oxygen to nitrite. P. denitrificans contains three main oxidases: cytochrome aa3, cytochrome o, and cytochrome co. Cytochrome o is proton translocating and receives its electrons from ubiquinol. Some properties of cytochrome co, which receives its electrons from cytochrome c, are reported.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Metabolic regulation including anaerobic metabolism in Paracoccus denitrificans. 205 Jun 53

Paracoccus denitrificans is able to grow on the C1 compounds methanol and methylamine. These compounds are oxidized to formaldehyde which is subsequently oxidized via formate to carbon dioxide. Biomass is produced by carbon dioxide fixation via the ribulose biphosphate pathway. The first oxidation reaction is catalyzed by the enzymes methanol dehydrogenase and methylamine dehydrogenase, respectively. Both enzymes contain two different subunits in an alpha 2 beta 2 configuration. The genes encoding the subunits of methanol dehydrogenase (moxF and moxI) have been isolated and sequenced. They are located in one operon together with two other genes (moxJ and moxG) in the gene order moxFJGI. The function of the moxJ gene product is not yet known. MoxG codes for a cytochrome c551i, which functions as the electron acceptor of methanol dehydrogenase. Both methanol dehydrogenase and methylamine dehydrogenase contain PQQ as a cofactor. These so-called quinoproteins are able to catalyze redox reactions by one-electron steps. The reaction mechanism of this oxidation will be described. Electrons from the oxidation reaction are donated to the electron transport chain at the level of cytochrome c. P. denitrificans is able to synthesize at least 10 different c-type cytochromes. Five could be detected in the periplasm and five have been found in the cytoplasmic membrane. The membrane-bound cytochrome c1 and cytochrome c552 and the periplasmic-located cytochrome c550 are present under all tested growth conditions. The cytochromes c551i and c553i, present in the periplasm, are only induced in cells grown on methanol, methylamine, or choline. The other c-type cytochromes are mainly detected either under oxygen limited conditions or under anaerobic conditions with nitrate as electron acceptor or under both conditions. An overview including the induction pattern of all P. denitrificans c-type cytochromes will be given. The genes encoding cytochrome c1, cytochrome c550, cytochrome c551i, and cytochrome c553i have been isolated and sequenced. By using site-directed mutagenesis these genes were mutated in the genome. The mutants thus obtained were used to study electron transport during growth on C1 compounds. This electron transport has also been studied by determining electron transfer rates in in vitro experiments. The exact pathways, however, are not yet fully understood. Electrons from methanol dehydrogenase are donated to cytochrome c551i. Further electron transport is either via cytochrome c550 or cytochrome c553i to cytochrome aa3. However, direct electron transport from cytochrome c551i to the terminal oxidase might be possible as well.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:C1 metabolism in Paracoccus denitrificans: genetics of Paracoccus denitrificans. 205 Jun 54

By using synthetic oligonucleotides, the gene encoding soluble cytochrome c550 was isolated from a genomic bank of Paracoccus denitrificans. The nucleotide sequence of the gene was determined, and the deduced amino acid sequence of the mature protein was found to be similar to the primary structure of purified cytochrome c550 except for the presence of seven additional amino acid residues at the C terminus. At the N terminus of the primary structure was found an additional stretch of 19 amino acid residues that had the typical features of the signal sequence of the cytochrome. Comparison of the nucleotide sequences of the upstream regions of the P. denitrificans cytochrome c550 gene and bc1 operon revealed three regions with a distinct organization that showed strong similarity. Downstream of the c550 gene was found part of another gene, the deduced amino acid sequence of which showed strong homology with subunit 1 of the cytochrome aa3 oxidase. For gene replacement experiments, the suicide vector pGRPd1 was constructed. The cytochrome c550 gene was inactivated by insertion of a kanamycin resistance gene, and the mutated gene was cloned into this vector. Recombination with the wild-type gene resulted in a mutant strain with an inactivated cytochrome gene. Isolated mutant strains were unable to synthesize the soluble cytochrome, as judged by spectrum analysis and analysis of periplasmic proteins by gel electrophoresis and heme staining. The mutation resulted in a 14% decrease in the growth yield during aerobic heterotrophic growth and in a 40% decrease in the maximum specific growth rate during growth on methylamine. Furthermore, a longer lag phase was observed under both growth conditions. The mutation had no effect on growth yield, maximum specific growth rate, and duration of the lag phase during anaerobic growth in the presence of nitrate. In addition, there was no accumulation of nitrite and nitrous oxide.
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PMID:Mutagenesis of the gene encoding cytochrome c550 of Paracoccus denitrificans and analysis of the resultant physiological effects. 215 63


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