Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A carrier protein mediating alanine transport was purified from the membranes of the thermophilic bacterium PS3, by ion exchange chromatography in the presence of both Triton X-100 and urea. The alanine carrier was recovered in the nonadsorbed fraction from either DEAE- or CM-cellulose columns, suggesting that its isoelectric point was in the neutral pH region. The final preparation contained virtually no electron transfer components, ATPase, or NADH dehydrogenase. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed that the final preparation consisted of two major protein components with molecular weights of 36,000 and 9,400. Active transport of alanine after incorporation of the alanine carrier into reconstituted proteoliposomes was driven not only by an artificial membrane potential generated by potassium ion diffusion via valinomycin but also by mitochondrial cytochrome oxidase incorporated into the same liposomes and supplemented with both cytochrome c and ascorbic acid. The membrane-integrated portion (TFo) of the ATPase complex uncoupled alanine transport by conducting protons across the membrane.
 ...
PMID:Isolation of the alanine carrier from the membranes of a thermophilic bacterium and its reconstitution into vesicles capable of transport. 19 18

1. Five subjects trained for 8 weeks on a bicycle ergometer for an average of 40 min/day, four times a week at a work load requiring 80% of the maximal oxygen uptake (V(O2 max.)). V(O2 max.) determinations were performed, and muscle biopsies from the quadriceps femoris muscle (vastus lateralis) were taken before, as well as repeatedly during, the training period. The muscle biopsies were histochemically stained for fibre-types (myofibrillar ATPase) and capillaries (amylase-PAS method), and analysed biochemically for succinate dehydrogenase and cytochrome oxidase activities.2. The training programme resulted in a 16% increase in V(O2 max.), a 20% increase in capillary density, a 20% increase in mean fibre area, and an approximately 40% increase in the activities of succinate dehydrogenase and cytochrome oxidase.3. The capillary supply to type I, IIA and IIB fibres, expressed as the mean number of capillaries in contact with each fibre-type, relative to fibre-type area, increased equally.4. The present study shows that endurance training constitutes a powerful stimulus for capillary proliferation in human skeletal muscle.
 ...
PMID:Capillary supply of the quadriceps femoris muscle of man: adaptive response to exercise. 19 32

The specific activity of markers-enzymes in the subcellular fractions of the rabbit visual analyzer cortical end, the synaptosomes and mitochondria of nerve cells, changed under the effect of early long deprivation. For cytochromoxidase and Na+, K+-ATPase it lowers considerably in all subfractions, for monoaminoxidase and Mg2+-ATPase it rises mainly in synaptosomes; the activity of acetyl cholinesterase lowers per 1 g of tissue. In the light two weeks later a tendency is observed to normalization of the studied indexes. The specific activity of cytochrome oxidase (except for free mitochondria) and Na+, K+-ATPase reaches the control, that of monoaminoxidase also partially normalizes, but not competely; Mg2+ATPase in all the subfractions is more inhibited than in the control. This evidences for the effect of light deprivation on the activity of the enzymes associated with different cycles of metabolic processes, first of all, of oxidation and ion transport. These changes are reversible when visual impulsation is recovered. Disturbances in chemism at the subcellular level are specific for different enzymic systems and are not the same in certain subfractions of great hemispheres.
 ...
PMID:[Effect of light deprivation on enzymic activity of synaptosomes and mitochondria of rabbit cortex visual region]. 19 70

1. Both valinomycin and p-trifluoromethoxy carbonyl cyanide phenylhydrazone (FCCP) are required for full release of respiration by cytochrome c oxidase-containing proteoliposomes (prepared by sonicating beef heart cytochrome aa3 in salt solution with 4 parts phosphatidylcholine, 4 parts phosphatidylethanolamine and 2 parts cardiolipin) in the presence of external ascorbate and cytochrome c. In the absence of valinomycin the response to FCCP is rather sluggish, as reported by Wrigglesworth et al. (1976) (Abstracts, 10th Int. Congr. Biochem., No. 06-6-230). 2. The Km for cytochrome c in 67 mM, pH 7.4, phosphate buffer with ascorbate as substrate, was 9 micrometer in both absence and presence of valinomycin and FCCP. Energization thus acts non-competitively towards cytochrome c oxidation. 3. The apparent Km for oxygen is greater in the energized than in the deenergized state; double reciprocal plots of respiration rate versus oxygen concentration are concave downward in the absence of uncouplers, as found with intact mitochondria. Energization thus acts "competitively" towards oxygen. 4. Despite the lack of a functional ATPase system, all the kinetic features of energization found in intact mitochondria can be mimicked in the reconstituted liposomes. This supports the chemiosmotic idea that electrical and perhaps H+ gradients modify the oxidase activity in reconstituted vesicles.
 ...
PMID:Control of respiration in proteoliposomes containing cytochrome aa3. I. Stimulation by valinomycin and uncoupler. 20 20

The kinetics of CO binding by the cytochrome c oxidase of pigeon heart mitochondria were studied as a function of membrane energization at temperatures from 180 to 280 degrees K in an ethylene glycol/water medium. Samples energized by ATP showed acceleration of CO binding compared to those untreated or uncoupled by carbonylcyanide p-trifluoromethyoxyphenylhydrazone but only at relatively low temperatures and high CO concentrations. Experiments using samples in a "mixed valency" (partially oxidized) state showed that the acceleration of ligand binding is not due to the formation of a partially oxidized state via reverse electron transport. It is concluded that in the deenergized state one CO molecule can be closely associated with the cytochrome a3 heme site without actually being bound to the heme iron; in the energized state, two or more ligand molecules can occupy this intermediate position. The change in the apparent ligand capacity of a region near the heme iron in response to energization is evidence for an interaction between cytochrome oxidase and the ATPase system. Furthermore, these results suggest a control mechanism for O2 binding.
 ...
PMID:The effect of mitochondrial energization on cytochrome c oxidase kinetics as measured at low temperatures. I. The reaction with carbon monoxide. 20 2

Effect of cuprizone has been studied on some biochemical properties of megamitochondria obtained from the mouse liver. (1) Contents of Ca2+, Mg2+ and Cu2+ in the blood or the liver homogenates were not altered by cuprizone intoxication, whereas those in liver mitochondria were significantly altered: after 3-4 days' intoxication, content of Ca2+ was decreased and was remarkably increased after 14-15 days' intoxication. Content of Mg2+ behaved contrarily. (2) Both cytochrome oxidase and ATPase activities were unchanged in the liver megamitochondria, but monoamine oxidase (MAO) activity was significantly decreased. Value of I50 (50% inhibition) for MAO was determined to be 0.33 mM using the control liver mitochondria. Cuprizone had almost no effect on MAO activity of kidney or heart mitochondria both in vivo and in vitro. (3) The amount of lysolecithin was increased in the liver megamitochondria. These results were discussed in the light of membrane fusion phenomenon which plays a key role in the mechanism of megamitochondrial formation.
 ...
PMID:Mechanism of the formation of megamitochondria by copper-chelating agents. V. Further studies on isolated megamitochondria. 20 65

Changes in the specific activity of cytochrome oxidase, monoamine oxidase, acetylcholinesterase and Na,K-ATPase in the light and heavy synaptosomes and mitochondria of neurone bodies fractions in the motor cerebral cortex of rabbits were demonstrated under conditions of light (visual) deprivation. These changes were specific of different metabolic cycles and differed in individual cell ultrastructures. The influence of sensory impulsation on functional neuron activity in different projection regions of the cerebral cortex is discussed.
 ...
PMID:[Biochemical characteristics of the synaptosomes and mitochondria of the motor area of the cerebral cortex following switching off of sensory impulsation]. 21 42

The apical and basal-lateral plasma membranes of toad bladder epithelium were radio-iodinated with the glucose-glucose oxidase-lactoperoxidase system. The covalently bound radio iodine was used as a marker during subcellular fractionation and membrane isolation. Homogenization conditions that ensured rupture of more than 80% of the cells without substantial nuclear damage were defined by Normarski optics. The nuclei were separated by differential centrifugation and the apical and basal-lateral components were resolved by differential and sucrose density gradient centrifugation. The apical components yielded two radioactive bands that were identified as glycocalyx and plasma membrane labeled with 125I. The basal-lateral components yielded a hetero-disperse pattern made up of at least 3 radioactive bands, but the bulk of the activity of ouabain-sensitive ATPase comigrated with only one of these bands. The mitochondia, identified by assays for cytochrome oxidase and NADH cytochrome c reductase activities, were separated from the radio-iodine labeled by centrifugation in sucrose density gradients under isokinetic conditions. The labeled glycocalyx and the slowly migrating components of basal-lateral labeling were separated from the radio-iodinated membranes by centrifugation at 100,000 x g x 1 hr after removal of the mitochrondria by the isokinetic method. The labeled membranes were then subjected to ultracentrifugation in sucrose density gradients under isopycnic conditions; the basal-lateral membranes containing ouabain-sensitive ATP-ase were well resolved from the apical membranes by this method. These results provide a relatively rapid method of attaining partial purification of the apical and basal-lateral plasma membranes of toad bladder epithelium.
 ...
PMID:Isolation of radio-iodinated apical and basal-lateral plasma membranes of toad bladder epithelium. 22 11

We propose that the UGA terminator regularly occurs as a tryptophan codon in yeast mitochondrial DNA. This conclusion is based on the sequence analysis of mitochondrial DNA regions coding for structural genes of cytochrome b, cytochrome oxidase, and the ATPase.
 ...
PMID:Use of the UGA terminator as a tryptophan codon in yeast mitochondria. 22 81

Human platelet plasma membranes were isolated with polylysine beads according to the technique developed by Jacobson and Branton (1977, Science [Wash. D. C.] 195:302--304). Lactoperoxidase-catalyzed surface iodination revealed that ninefold greater 125I specific activity was associated with the membranes isolated on beads than with whole platelets. Enrichment in the bead membrane preparation of the activities of membrane marker enzymes, bis(p-nitrophenyl)phosphate phosphodiesterase and Na,K-ATPase, was 8.0 and 4.4, respectively. Contamination with enzymes of other organelles, cytochrome oxidase and beta-glucuronidase, was relatively low as compared with membranes isolated by sucrose gradient centrifugation. Analysis by SDS polyacrylamide gel electrophoresis showed that a full complement of surface glycoproteins was present on the membranes isolated with polylysine beads. The polylysine bead technique is a rapid, reproducible and efficient method for the preparation of relatively pure platelet plasma membranes.
 ...
PMID:Isolation of human platelet plasma membranes with polylysine beads. 22 8


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>