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)

Comparison of the human mitochrondial DNA sequence of the cytochrome oxidase subunit II gene and the sequence of the corresponding beef heart protein shows that UGA is used as a tryptophan codon and not as a termination codon and suggests that AUA may be a methionine and not an isoleucine codon. The cytochrome oxidase II gene is contiguous at its 5' end with a tRNAAsp gene and there are only 25 bases at its 3' end before a tRNALys gene. These tRNA'S are different from all other known tRNA sequences.
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PMID:A different genetic code in human mitochondria. 22 94

The terminal cytochrome c1aa3 of the respiratory chain of Thermus thermophilus has been isolated and purified to homogeneity by a novel procedure. The two subunit proteins (55 and 33 kDa) have been characterized chemically. Computer searches with partial amino acid sequences obtained from both subunits show that the larger subunit belongs to the cytochrome oxidase subunit I protein family while the smaller covalently heme-binding subunit is not a cytochrome c1 but appears to be a fused protein between cytochrome c and cytochrome oxidase subunit II. With respect to the 16-S rRNA-derived phylogeny of procaryotes, the results show that the genetic information for an O2-reacting cytochrome oxidase (EC 1.9.3.1) existed already in early eubacteria.
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PMID:Evidence for cytochrome oxidase subunit I and a cytochrome c--subunit II fused protein in the cytochrome 'c1aa3' of Thermus thermophilus. How old is cytochrome oxidase? 254 Sep 68

The proteolytic processing of the mitochondrially encoded subunit II of cytochrome oxidase is prevented by the yeast mutation ts2858. We report that the mutant is, in addition, temperature sensitive for the processing of cytochrome b2, a protein encoded by nuclear DNA. Thus the same mutation affects the removal of pre-sequences from a mitochondrially encoded inner membrane protein and from an imported soluble protein located in the intermembrane space. The mutation blocks the second processing step of cytochrome b2. The cytochrome b2 intermediate accumulates in the mutant at 36 degrees C and assumes its enzyme activity. At 23 degrees C the conversion to the mature protein is considerably slower than in wild-type cells. The similarity of the cleavage sites Asn-Asp and Asn-Glu of the precursors for cytochrome oxidase subunit II and cytochrome b2, respectively, suggests a sequence-specific recognition by one protease or a factor activating a protease. On the other hand maturation of cytochrome c peroxidase, another enzyme of the intermembrane space, is not affected by the pet ts2858 mutation.
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PMID:One nuclear gene controls the removal of transient pre-sequences from two yeast proteins: one encoded by the nuclear the other by the mitochondrial genome. 301 96

Subunit II of cytochrome oxidase is encoded by the mitochondrial OXI1 gene in Saccharomyces cerevisiae. The temperature-sensitive nuclear pet mutant ts2858 has an apparent higher mol. wt. subunit II when analyzed on lithium dodecylsulfate (LiDS) polyacrylamide gels. However, on LiDS-6M urea gels the apparent mol. wt. of the wild-type protein exceeds that of the mutant. Partial revertants of mutant ts2858 that produce both the wild-type and mutant form of subunit II were isolated. The two forms of subunit II differ at the N-terminal part of the molecule as shown by constructing and analyzing nuclear ts2858 and mitochondrial chain termination double mutants. The presence of the primary translation product in the mutant and of the processed form in the wild-type lacking 15 amino-terminal residues was demonstrated by radiolabel protein sequencing. Comparison of the known DNA sequence with the partial protein sequence obtained reveals that six of the 15 residues are hydrophilic and, unlike most signal sequences, this transient sequence does not contain extended hydrophobic parts. The nuclear mutation ts2858 preventing post-translational processing of cytochrome oxidase subunit II lies either in the gene for a protease or an enzyme regulating a protease.
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PMID:A nuclear mutation prevents processing of a mitochondrially encoded membrane protein in Saccharomyces cerevisiae. 631 50

Previously, we showed that predominant expression of the N-methyl-D-aspartate (NMDA) receptor in the neurons of the sexually dimorphic nucleus of the preoptic area of male rats plays an important role in preventing neurons from apoptosis during sexual development. Blocking of the NMDA receptor by dizocilpine ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-iminemaleate (MK-801) causes down-regulation of some survival-related genes including cytochrome oxidase subunit II (COII), a mitochondria-encoded complex IV subunit, which in turn induces ATP depletion and the occurrence of apoptosis. The aim of this study is to investigate the molecular events during down-regulation of the COII gene expression induced by blocking of the NMDA receptor. Treatment of the GnRH cell line (GT1-7) with MK-801 caused 1) a decrease of intracellular calcium concentration ([Ca2+]i) after 20 h; 2) significant decreases of the levels of peroxisome proliferator-activated receptor coactivator-1 (PGC-1) mRNA and protein after 24 h; 3) down-regulation of COII mRNA after 36 h; and 4) the occurrence of neuronal apoptosis after 48 h. Accordingly, we hypothesize that blocking of the NMDA receptor may cause a decrease of the [Ca2+]i, which in turn inhibits the expressions of PGC-1 and COII and then leads to subsequent neuronal apoptosis.
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PMID:The molecular events occur during MK-801-induced cytochrome oxidase subunit II down-regulation in GT1-7 cells. 1760 85

The objective of this study was to assess the expression of mitochondrial proteins and oxidized proteins in heart muscle homogenate obtained from male broilers exhibiting either high or low feed efficiency (G:F) phenotypes. Tissue homogenate was prepared from ventricular tissue obtained from broilers with high (0.80+/-0.01, n=8) and low (0.62+/-0.02, n=8) FE. The levels of specific immunoreactive proteins and oxidized proteins (carbonyls) were determined using Western blot analysis. The expression of 6 electron transport chain proteins [complex II, 70S subunit (CII 70S); iron-sulfur-containing protein (ISP), cytochrome b (Cyt b), cytochrome (Cyt c1) (of complex III); and cytochrome oxidase subunit II (COX II) (of complex IV)] and adenine nucleotide translocator 1 (ANT1) were higher in low feed efficiency heart mitochondria, but 1 protein [NAD subunit 6c (NAD6c) (complex I)] was higher in high feed efficiency birds. Protein carbonyl levels, indicative of oxidized proteins, were higher in heart tissue of low compared with high feed efficiency broilers.
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PMID:Investigation of mitochondrial protein expression and oxidation in heart muscle in low and high feed efficient male broilers in a single genetic line. 2007 89

The coding and flanking sequences of the 18S-5S ribosomal RNA genes and the cytochrome oxidase subunit II gene of Zea diploperennis mitochondrial DNA have been determined and compared to the corresponding sequences of normal maize (Zea mays L.) Both length and substitution mutations are found in the coding region of the 18S rRNA gene, whereas only one substitution mutation is found in the coding region of cytochrome oxidase II. Sequence divergence between maize and Zea diploperennis is about one-tenth of that between wheat and maize. The rate of nucleotide divergence by base substitution is less for plant mitochrondrial genes than for comparable genes in animal mitochondria.
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PMID:Sequence of the 18S-5S ribosomal gene region and the cytochrome oxidase II gene from mtDNA of Zea diploperennis. 2424 Mar 40