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)

Peroxisome proliferation has been induced with 2-methyl-2-(p-[1,2,3,4-tetrahydro-1-naphthyl]-phenoxy)-propionic acid (Su-13437). DNA, protein, cytochrome oxidase, glucose-6-phosphatase, and acid phosphatase concentrations remain almost constant. Peroxisomal enzyme activities change to approximately 165%, 50%, 30%, and 0% of the controls for catalase, urate oxidase, L-alpha-hydroxy acid oxidase, and D-amino acid oxidase, respectively. For catalase the change results from a decrease in particle-bound activity and a fivefold increase in soluble activity. The average diameter of peroxisome sections is 0.58 +/- 0.15 mum in controls and 0.73 +/- 0.25 mum after treatment. Therefore, the measured peroxisomal enzymes are highly diluted in proliferated particles. After tissue fractionation, approximately one-half of the normal peroxisomes and all proliferated peroxisomes show matric extraction with ghost formation, but no change in size. In homogenates submitted to mechanical stress, proliferated peroxisomes do not reveal increased fragility; unexpectedly, Su-13437 stabilizes lysosomes. Our results suggest that matrix extraction and increased soluble enzyme activities result from transmembrane passage of peroxisomal proteins. The changes in concentration of peroxisomal oxidases and soluble catalase after Su-13437 allow the calculation of their half-lives. These are the same as those found for total catalase, in normal and treated rats, after allyl isopropyl acetamide: about 1.3 days, a result compatible with peroxisome degradation by autophagy. A sequential increase in liver RNA concentration, [14C]leucine incorporation into DOC-soluble proteins and into immunoprecipitable catalase, and an increase in liver size and peroxisomal volume per gram liver, characterize the trophic effect of the drug used. In males, Su-13437 is more active than CPIB, another peroxisome proliferation-inducing drug; in females, only Su-13437 is active.
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PMID:Structure, composition, physical properties, and turnover of proliferated peroxisomes. A study of the trophic effects of Su-13437 on rat liver. 0 Apr 6

The relationship of enzymatic activity to organelle development and organelle number during differentiation of the metanephric kidney in the mouse was approached from several experimental directions. Biochemical analyses of marker enzymes for peroxisomes (catalase and D-amino acid oxidase), mitochondria (cytochrome oxidase) and lysosomes (acid phosphatase) were performed on kidneys at ages from 17 days prenatal to adult. These data were correlated with a morphometric analysis of populations of peroxisomes and mitochondria in differentiating cells of the proximal tubule. Postnatal development of the metanephric kidney was found to be accompanied by a rapid increase in both the specific activity of catalase and the number of peroxisomes per 100 mu2 in the proximal tubule during the first 4 weeks of postnatal growth. Elaboration of the endoplasmic reticulum (ER) was seen to parallel the increase in number of peroxisomes to which segments of ER were often in close apposition. Extensive interactions between segments of ER and peroxisomes were readily visible in 0.5-mu sections viewed in the high voltage electron microscope. In contrast to peroxisomes, neither mitochondria nor lysosomes followed a similar pattern of net organelle increase, suggesting that a defined population density of mitochondria and lysosomes may exist in the proximal tubule at birth, prior to complete development of the kidney.
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PMID:Peroxisome development in the metanephric kidney of mouse. 0 Apr 40

The PolytronR and Dounce homogenizers have been evaluated for preparation of homogenates of rat liver prior to isolation of subcellular fractions by differential centrifugation. Marker enzymes used to evaluate the subcellular fractions included cytochrome oxidase, monoamine oxidase, D-amino acid oxidase, acid phosphatase, glucose-6-phosphatase, ethyl morphine demethylase, and lactate dehydrogenase. No significant difference in the distribution of enzymes (percent recovery or specific activity) was observed between the two methods of homogenization. In addition, there were no significant differences in the ultrastructural appearances and respiratory control ratios of the mitochondrial fractions prepared by the two methods of homogenization.
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PMID:Preparation of subcellular fractions from rat liver: comparison of the Polytron with the Dounce homogenizer. 18 48

Experiments were carried out to determine if the difference in rates of cell proliferation between normal and neoplastic cells may be related to altered levels of oxidative enzymes. Assays were performed using homogenates from hepatocellular carcinoma HC-252, a rapidly growing and moderately well-differentiated tumor; from normal liver; and from the liver of the tumor-bearing ACI rat. Results of the mitochondrial enzymes indicated that the activities of cytochrome oxidase and succinate dehydrogenase were 3-fold lower in tumor homogenates than in liver homogenates. Monoamine oxidase activity could not be detected in HC-252; mixing experiments indicated no inhibitor was present in HC-252. Activities of th peroxisomal enzymes, urate oxidase, D-amino acid oxidase, and L-alpha-hydroxy acid oxidase were either undetected in the tumor or were 12-fold lower than in liver homogenates. The activity of xanthine oxidase, a cytoplasmic enzyme, was 5- to 6-fold lower in the tumor. Catalase activity in the tumor was also lower than in liver; this may be indicative of a lower oxidative environment at the cellular level. These enzyme activities of the liver of tumor-bearing rats were in the same range as those of normal rat liver, except that D-amino acid oxidase activity was slightly lower, and catalase activity was markedly lower and varied in a wide range. These results show an inverse correlation between the activities of oxygen-utilizing enzymes and rates of proliferation of one tumor line and its control. The possible implications of these results in neoplasia, cell proliferation, and cellular aging are discussed.
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PMID:Oxidoreductase activities in normal rat liver, tumor-bearing rat liver, and hepatoma HC-252. 689 80