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)

Nuclear mutants of Saccharomyces cerevisiae assigned to complementation group G34 are respiratory-deficient and lack cytochrome oxidase activity and the characteristic spectral peaks of cytochromes a and a(3). The corresponding gene was cloned by complementation, sequenced, and identified as reading frame YGR062C on chromosome VII. This gene was named COX18. The COX18 gene product is a polypeptide of 316 amino acids with a putative amino-terminal mitochondrial targeting sequence and predicted transmembrane domains. Respiratory chain carriers other than cytochromes a and a(3) and the ATPase complex are present at near wild-type levels in cox18 mutants, indicating that the mutations specifically affect cytochrome oxidase. The synthesis of Cox1p and Cox3p in mutant mitochondria is normal whereas Cox2p is barely detected among labeled mitochondrial polypeptides. Transcription of COX2 does not require COX18 function, and a chimeric COX3-COX2 mRNA did not suppress the respiratory defect in the null mutant, indicating that the mutation does not impair transcription or translation of the mRNA. Western analysis of cytochrome oxidase subunits shows that inactivation of the COX18 gene greatly reduces the steady state amounts of subunit 2 and results in variable decreases in other subunits of cytochrome oxidase. A gene fusion expressing a biotinylated form of Cox18p complements cox18 mutants. Biotinylated Cox18p is a mitochondrial integral membrane protein. These results indicate Cox18p to be a new member of a group of mitochondrial proteins that function at a late stage of the cytochrome oxidase assembly pathway.
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PMID:Cloning and characterization of COX18, a Saccharomyces cerevisiae PET gene required for the assembly of cytochrome oxidase. 1080 34

Parietal cells in the rat oxyntic mucosa were analyzed by the immunofluorescence pattern of the proton pump. The adult rats were grouped into fasting (C), gastrin-treated (G), and ranitidine-treated (R) groups, gastric pH was measured, and the stomach was processed for immunohistochemistry. The fluorescence of parietal cells showed a reticular, diffuse, or mixed pattern in cytoplasm. Quantitatively, 53% of the total cells showed the reticular pattern in group G (pH 1.9), 44% in group C (pH 2.0), and 0% in group R (pH 6.7). On the other hand, 7.0% of the total cells showed the diffuse pattern in group G, 11.9% in group C, and 56.2% in group R. The results indicated that the staining pattern depended on the activity of acid secretion. In addition, the proportion of parietal cells showing the reticular pattern decreased in the following order, the superficial, middle, and deep third of the mucosa, and the diffuse pattern showed the opposite trend. This suggests that the acid secretion is more active in parietal cells in the superficial part of the mucosa. The double staining with proton pump-specific and cytochrome oxidase-specific antibodies revealed the close relation between reticular fluorescence and mitochondria.
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PMID:Immunofluorescence detection of gastric H(+)/K(+)-ATPase and its alterations as related to acid secretion. 1181 94