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)

The complete amino acid sequence of the heme alpha-containing subunit V of bovine heart cytochrome oxidase was determined to be: H2N-Ser-His-Gly-Ser-His-Glu-Thr-Asp-Glu-Glu-Phe-Asp-Ala-Arg-Trp-Val-Thr-Tyr-Phe-Asn-Lys-Pro-Asp-Ile-Asp-Ala-Trp-Glu-Leu-Arg-Lys-Gly-Met-Asn-Thr-Leu-Val-Gly-Tyr-Asp-Leu-Val-Pro-Glu-Pro-Lys-Ile-Ile-Asp-Ala-Ala-Leu-Arg-Ala-Cys-Arg-Arg-Leu-Asn-Asp-Phe-Ala-Ser-Ala-Val-Arg-Ile-Leu-Glu-Val-Val-Lys-Asp-Lys-Ala-Gly-Pro-His-Lys-Glu-Ile-Tyr-Pro-Tyr-Val-Ile-Gln-Glu-Leu-Arg-Pro-Thr-Leu-Asn-Glu-Leu-Gly-Ile-Ser-Thr-Pro-Glu-Glu-Leu-Gly-Leu-Asp-Lys-Val-COOH. The subunit V is a single polypeptide which consists of 109 amino acid residues. The protein contains 48.6% hydrophobic residues and 34.0% hydrophilic residues and it is an acidic protein having a net charge of -3 at neutral pH. The molecular weight of subunit V was calculated to be 12,436 and that for the heme alpha-containing polypeptide was 13,295.
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PMID:Amino acid sequence of subunit V of bovine heart cytochrome oxidase, the heme alpha-containing subunit. 22 Feb 24

The gene (coxII) encoding subunit II of Rhodobacter sphaeroides cytochrome c oxidase (cytochrome aa3) has been isolated by screening a genomic DNA library in phage lambda with a probe derived from coxII of Paracoccus denitrificans. A 2-kb fragment containing coxII DNA was subcloned into the phage M13mp18 and the sequence determined. The 2-kb insert contains the entire coding region for coxII gene, including the ATG start codon and a TGA stop codon. The deduced amino acid (aa) sequence of subunit II of R. sphaeroides shows regions of substantial homology to the corresponding subunit of the bovine mitochondrial oxidase (63% overall) and P. denitrificans oxidase (68% overall). The postulated redox-active copper ion (CuA) binding site involving two Cys and two His residues (as well as an alternative Met residue) is conserved among these species, along with four invariant acidic aa residues (two Asp and two Glu) that may be involved in interactions with cytochrome c, and a region of aromatic residues (Tyr-Gln-Trp-Tyr-Trp-Gly-Tyr-Glu-Tyr) which is postulated to play a role in electron transfer. Hydropathy profile analysis suggests that while the bovine COXII secondary structure contains two transmembrane helices, the R. sphaeroides subunit II has a third such helix that may function as part of a signal sequence, as suggested for P. denitrificans.
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PMID:The gene encoding cytochrome c oxidase subunit II from Rhodobacter sphaeroides; comparison of the deduced amino acid sequence with sequences of corresponding peptides from other species. 164 8

The cellular uptake and laminar distribution of tritium-labeled gamma-aminobutyrate, aspartate, glutamate and glycine were examined in the primary visual cortex of squirrel monkeys. The purpose was to correlate the distribution of these labeled neurons with their level of cytochrome oxidase activity, particularly in laminae II-III (puffs) and adjacent non-puff regions. In general, tritium-labeled neurons that had either high or low levels of cytochrome oxidase activity were present in all laminae with each amino acid tested; however, their density varied between laminae and with the amino acid injected. Specifically, in laminae II-III, very few neurons were labelled with either of the putative excitatory amino acids (aspartate and glutamate). An increased uptake for both was observed in lamina IVC, with the greatest increase for each occurring in laminae V and VI. Significantly more neurons in each lamina were labeled with the putative inhibitory transmitters (gamma-aminobutyrate and glycine) than with either aspartate or glutamate. gamma-Aminobutyrate-labeled neurons were more prevalent in lamina II than III, and an increase in labeling was observed in laminae IV-VI, with the most prominent increase found in laminae V and VI. Glycine-labeled neurons were larger, more uniformly distributed and more abundant throughout all cortical laminae than those labeled with the other amino acids. Significantly more gamma-aminobutyrate- and glycine-labeled neurons were found in the puff regions than in the non-puff areas. No difference was found between puff and non-puff regions for the tritium-labeled leucine controls. Labeled neurons included stellate, fusiform and pyramidal-shaped cells of varying sizes; however, gamma-aminobutyrate-labeled pyramidal cells were not observed outside of the intense injection site. Large glycine-labeled cytochrome-oxidase-reactive pyramidal cells (24-32 micron in diameter) were present at the boundary between laminae V and VI. In addition, a row of large glycine-labeled, fusiform neurons were present in lamina IVB. With each amino acid injected, the tritium-labeled neurons that were darkly reactive for cytochrome oxidase were, on average, larger than the tritium-labeled neurons that were only lightly reactive for cytochrome oxidase. Thus, each of the four amino acids tested had its unique pattern of distribution in the primate striate cortex. Whether one or all of them served as neurotransmitter(s) for distinct neuronal groups is beyond the scope of this study. Glycine, in particular, might be used in part or in whole for metabolic purposes.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Correlation between cytochrome oxidase staining and the uptake and laminar distribution of tritiated aspartate, glutamate, gamma-aminobutyrate and glycine in the striate cortex of the squirrel monkey. 241 91

Mutation of conserved Phe-82 of yeast iso-1 cytochrome c to Tyr, Gly, Ser, Leu, or Ile affects binding to and reaction with cytochrome-c oxidase from beef heart. The observed changes of binding and kinetic constants reflect mutation-induced rearrangements in the heme vicinity brought about by the replacement of Phe-82. Such conformational rearrangements are also revealed by altered circular dichroism spectra of the oxidase-bound mutant cytochromes c. Variations in Km for cytochrome c oxidation do not parallel variations in Kd, the dissociation constant for binding of cytochrome c to the oxidase. This observation does not support an enzymatic mechanism in which the rate of cytochrome c oxidation is governed by product dissociation.
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PMID:Binding and oxidation of mutant cytochromes c by cytochrome-c oxidase. 253 28

The yeast box-mutant W7 exhibits deficiencies in cytochrome b and in nuclear coded complex III subunits, a phenotype observed previously in a patient with mitochondrial myopathy. DNA sequence analysis of mutant W7 revealed a single base transition in the cytochrome b gene; the mutated residue Gly 131 is perfectly conserved in all known cytochromes b and belongs to the Qo domain. Mutant W7 provides a model system for evaluating the action of therapeutic agents, such as vitamin K3 which restored NADH-oxidase activity in the mutant as well as in the antimycin-inhibited wild type. However, with the mutant, a greater quantity of menadione was necessary due to a decrease in other complex activities, and a much lower electron-flow fraction passed through cytochrome oxidase.
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PMID:Electron-transfer restoration by vitamin K3 in a complex III-deficient mutant of S. cerevisiae and sequence of the corresponding cytochrome b mutation. 255 31

The neuronal uptake and laminar distribution of cortically injected tritium-labeled gamma-aminobutyrate (GABA), aspartic acid, glutamate and glycine was examined in the prestriate cortex of squirrel monkeys. The intent of this investigation was not to examine the role of these amino acids as neurotransmitters, but to correlate the distribution of tritium-labeled neurons with their levels of cytochrome oxidase activity. A comparison of the number of these labeled neurons was made between the metabolically active "puff" and the less active "nonpuff" regions. In addition, these results were contrasted with the findings in area 17. With each tritiated amino acid tested, labeled neurons that had either high or low levels of cytochrome oxidase activity were present in all laminae. However, the density of labeled neurons varied between lamina for a given amino acid as well as between different amino acids. While many neurons that were cytochrome oxidase-reactive were also tritium-labeled, cytochrome oxidase activity was not a prerequisite for the sequestering of tritium label. In fact, many of the labeled neurons exhibited relatively low levels of cytochrome oxidase activity. Similar to area 17, few aspartate- or glutamate-labeled neurons were present in laminae II-III. The number of labeled neurons for both amino acids increased in laminae IV-VI, with the greatest increase observed in laminae V-VI. Gamma-aminobutyrate-labeled neurons were more prevalent in laminae I and upper II than in the other laminae, whereas in area 17, a greater proportion of the labeled neurons were found in laminae V-VI. With the exception of the uppermost laminae, where GABA-labeled neurons were more abundant, the number of glycine-labeled neurons was significantly greater throughout most laminae than with the other amino acids examined. The density of glycine-labeled neurons in lamina IV, however, was significantly less than the number observed in lamina III even though lamina III was farther away from the injection site which was at the boundary between laminae V-VI. Glycine-labeled neurons were, on average, larger than those labeled with any other amino acid. Similar to area 17, more GABA- and glycine-labeled neurons were observed within the puff regions than in nonpuff regions. No puff/nonpuff differences were observed in the distribution of leucine-injected controls. Labeled neurons for each amino acid included stellate-, fusiform- and pyramidal-shaped cells, each of varying sizes. However, outside the intensely labeled injection sites, no GABA-labeled pyramidal cells were observed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Neuronal uptake and laminar distribution of tritiated aspartate, glutamate, gamma-aminobutyrate and glycine in the prestriate cortex of squirrel monkeys: correlation with levels of cytochrome oxidase activity and their uptake in area 17. 289 Jan 20

Phenylalanine 87 of yeast iso-1-cytochrome c (Phe 82 in horse heart and bonito) is phylogenetically conserved and occurs near the surface of the protein. It has been suggested that this residue is directly involved in electron transfer between cytochrome c and cytochrome c peroxidase (CCP) and may also control the polarity of the haem environment. Because Phe residues are not susceptible to chemical modification, no direct means of studying the functional role of Phe 87 has been available, so we have chosen Phe 87 as our initial target here to test the feasibility of using site-directed mutagenesis as a means of studying structure-function relationships in cytochrome c. We have changed the codon for Phe 87 to that of either a Ser, a Tyr or a Gly. The mutated genes have been introduced into a yeast strain lacking both isozymes of cytochrome c. Unlike the recipient strain, transformants grow on a non-fermentable carbon source, indicating that the mutant proteins can reduce cytochrome oxidase. The purified mutant proteins are similar to wild type with respect to their visible spectra, 20-70% as active as wild-type protein in the CCP assay, and their reduction potentials are lowered by as much as 50 mV. Thus Phe 87 is not essential for cytochrome c to transfer electrons but is involved in determining the reduction potential.
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PMID:Site-directed mutagenesis of cytochrome c shows that an invariant Phe is not essential for function. 298 14

Metabolism of glycine in isolated mitochondria and protoplasts was investigated in photosynthetic, etiolated (barley and pea leaves) and fat-storing (maize scutellum) tissues using methods of [1-(14)C]glycine incorporation and counting of 14CO2 evolved, oxymetric measurement of glycine oxidation and rapid fractionation of protoplasts incubated in photorespiratory conditions with consequent determination of ATP/ADP ratios in different cell compartments. The involvement of different paths of electron transport in mitochondria during operation of glycine decarboxylase complex (GDC) was tested in different conditions, using aminoacetonitrile (AAN), the inhibitor of glycine oxidation in mitochondria, rotenone, the inhibitor of Complex I of mitochondrial electron transport, and inhibitors of cytochrome oxidase and alternative oxidase. It was shown that glycine has a preference to other substrates oxidized in mitochondria only in photosynthetic tissue where succinate and malate even stimulated its oxidation. Rotenone had no or small effect on glycine oxidation, whereas the role of cyanide-resistant path increased in the presence of ATP. Glycine oxidation increased ATP/ADP ratio in cytosol of barley protoplasts incubated in the presence of CO2, but not in the CO2-free medium indicating that in conditions of high photorespiratory flux oxidation of NADH formed in the GDC reaction passes via the non-coupled paths. Activity of GDC in fat-storing tissue correlated with the activity of glyoxylate-cycle enzymes, glycine oxidation did not reveal preference to other substrates and the involvement of paths non-connected with proton translocation was not pronounced. It is suggested that the preference of glycine to other substrates oxidized in mitochondria is achieved in photosynthetic tissue by switching to rotenone-insensitive intramitochrondrial NADH oxidation and by increasing of alternative oxidase involvement in the presence of glycine.
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PMID:Involvement of cyanide-resistant and rotenone-insensitive pathways of mitochondrial electron transport during oxidation of glycine in higher plants. 925 32

Since yeast is amenable to mitochondrial transformation, designed mutations can be introduced in the mitochondrially encoded subunits of the respiratory complexes. In the present work, six mutations have been introduced by the biolistic method into yeast (Saccharomyces cerevisiae) cytochrome oxidase subunits I and III. The effects of these mutations on respiratory growth competence, cytochrome oxidase activity and optical properties were then characterized. Firstly, the conserved glutamate Glu-243 in the D-channel of subunit I was replaced by an asparagine or an aspartate residue. The effects of the mutations showed that Glu-243, which is essential for proton movement in bacterial oxidases, is also required for the activity of the eukaryotic enzyme. Secondly, four mutations associated with human disease were introduced in yeast, allowing detailed analysis of their deleterious effects on cytochrome oxidase function: Met-273-->Thr, Ile-280-->Thr and Gly-317-->Ser, affecting residues located in or near the K-channel in subunit I, and a short in-frame deletion comprising residues Phe-102 to Phe-106 in subunit III (DeltaF102-F106). The subunit III mutation was highly deleterious and abolished enzyme assembly. The change Gly-317-->Ser had no effect on respiratory function. However, mutations Met-273-->Thr and Ile-280-->Thr were mildly deleterious, decreased cytochrome oxidase activity and slightly perturbed the properties of the binuclear centre.
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PMID:Site-directed mutations in the mitochondrially encoded subunits I and III of yeast cytochrome oxidase. 1117 Nov 20

Phagocytes of the compound ascidian Botryllus schlosseri are capable of constitutive macropinocytosis (MP) at sites of membrane ruffling along the leading edge. This gives rise to the formation of initially irregular vesicles which then move to the inside of the cells and acquire a more regular morphology. Both phagocyte spreading and MP are enhanced by the recognition of molecules containing the sequence Arg-Gly-Asp (RGD): this suggests that, as in mammals, integrin activation is involved in the induction of both cell spreading and endocytosis. The occurrence of MP is associated with increased oxygen consumption and a rise in the production of superoxide anion, as indicated by nitroblue tetrazolium reduction, and ATP, as indicated by increased cytochrome oxidase activity. On the whole, our results indicate the conservation of common mechanisms of MP induction throughout the Chordate phylum.
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PMID:RGD-containing molecules induce macropinocytosis in ascidian hyaline amoebocytes. 1640 1


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