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)

In populations of cultured arterial endothelial and smooth muscle cells grown under the same conditions, we have measured the total activity per cell of 10 enzymes commonly used as "markers" for subcellular organelles: NADH: ferricyanide reductase, NADH:cytochrome c reductase (rotenone insensitive). NADPH:cytochrome c reductase, alpha-glucosidase, 5'-nucleotidase, alkaline phosphodiesterase I, cytochrome oxidase, monoamine oxidase, cathepsin D, and N-acetyl-beta-glucosaminidase. Significant differences between the cell types were found for 7 of the 10 enzymes tested. The total activity of 5'-nucleotidase in cultured smooth muscle cells was 17 times that of cultured endothelial cells. Comparison of the activities in the two cell types freshly collected and in culture showed that the difference in 5'-nucleotidase in cultured cells is due principally to loss of activity from endothelial cells, suggesting that this activity is regulated differently in the two cell types. In both cell types cathepsin D activity rose during culture.
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PMID:Enzyme activities in endothelial cells and smooth muscle cells from swine aorta. 22 46

Homogenates of HTC cells have been fractionated by differential centrifugation (in four particulate fractions: N, M, L, P, and a supernatant S) or isopycnic banding in linear sucrose gradients. On this basis, the following subcellular organelles may be characterized: (i) Mitochondria, detected by cytochrome oxidase and succinodehydrogenase, are collected in the M and L fractions, and equilibrate, as a narrow band, at a median buoyant density of 1.18 g/cm3. (ii) Lysosomes, detected by the latent hydrolases beta-glycerophosphatase and N-acetyl-beta-glucosaminidase, are largely sedimented in the M and L fractions, and display a broad density distribution pattern with a median value of 1.17 g/cm3. This density is decreased or increased after cultivation of the cells in presence of Triton WR-1339 or Dextran 500, respectively. The behavior of cathepsin D is somewhat at variance with that of the two other hydrolases. (iii) Plasma membrane is tentatively detected by alkaline phosphodiesterase I. Largely recovered in the P fraction, this enzyme equilibrates at a median density close to that of the lysosomal hydrolases; the bulk of cholesterol and about half of the leucyl-2-naphthylamidase are closely associated with alkaline phosphodiesterase I; HTC cells do not contain typical 5'-nucleotidase. (iv) Catalase-bearing particles, of high buoyant density (1.22 g/cm3) are present, but 30-40% of the catalase is also found readily soluble. NADPH- and NADH: cytochrome c reductase, and RNA show more complex distributions. It is suggested that the former enzyme is associated with the endoplasmic reticulum; as in liver, NADH reductase activity is shared between the endoplasmic reticulum and the mitochondria; half of the RNA is associated with free ribosomes of polysomes. True glucose-6-phosphatase could not be detected.
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PMID:Analytical fractionation of cultured hepatoma cells (HTC cells). 56 43

As a first step in studies on the molecular mechanism(s) underlying gentamicin toxicity, the effect of treating rats with this aminoglycoside antibiotic (100 mg/kg once or twice daily for 3 days) on the analytical subfractionation of the kidney cortex has been examined. DNA was used as a marker for the nuclei, cytochrome oxidase for mitochondria, acid phosphatase for lysosomes, catalase for peroxisomes (with reservations; see the companion paper), NADPH-cytochrome c reductase for the endoplasmic reticulum, p-nitrophenyl-alpha-mannosidase (at pH 5.5) for the Golgi apparatus, AMPase for the plasma membrane in general and alkaline phosphatase for the brush border, and lactate dehydrogenase for the cytosol. In addition, the presumptive lysosomal hydrolases N-acetyl-beta-D-glucosaminidase, p-nitrophenyl-alpha-mannosidase (at pH 4.5), cathepsin D, and DNase II were monitored. Electron microscopy was also performed on the subfractions obtained. The only significant biochemical changes brought about by gentamicin treatment were that N-acetyl-beta-D-glucosaminidase demonstrated both a greater total activity and a larger enrichment in the 104,000gav pellet, while p-nitrophenyl-alpha-mannosidase at pH 4.5 demonstrated the same total activity and a greater enrichment in the 104,000gav pellet. Since myeloid bodies were shown by electron microscopy to sediment primarily with the 500gav and 10,000gav pellets, the biochemical changes seen cannot be associated with these morphological structures. These findings suggest that selective changes in a certain subpopulation(s) of lysosomes or in certain lysosomal enzymes may be involved in the early stages of gentamicin toxicity. On the other hand, no lysosomal membrane damage was observed here, since both the latency of acid phosphatase and the recovery of this activity in the soluble cytosol were unchanged. The present investigation may also have relevance for the dosage and duration of gentamicin treatment chosen in clinical situations.
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PMID:Biochemical effects of gentamicin on rat kidney cortex. II. Analytical subfractionation after short-term, high-dose treatment. 303 Aug

Postnuclear supernates from homogenates of skeletal muscle from rats subjected to starvation, injections of Triton WR-1339, dextran-500, and dextran + corticosterone were fractionated by means of rate and isopycnic zonal centrifugation in sucrose-0.02 M KCl gradients. Zonal fractions were analyzed for protein, RNA, cytochrome oxidase, and up to six acid hydrolases. The results indicate the presence of two groups of lysosome-like particles. One group contributes approximately 95% of the cathepsin D and acid phosphatase activity and 75% of the acid ribonuclease, beta-glucuronidase, and arylsulfatase activity in muscle. It is characterized by a modal equilibrium density of 1.18 that is decreased by starvation, but is not shifted by dextran-500 or Triton WR-1339. The second group has a higher proportion of acid ribonuclease, beta-glucuronidase, and arylsulftase; the equilibrium density can be shifted by dextran-500 and Triton WR-1339. It is suggested that this group of lysosomes is derived from macrophages and other connective tissue cells, whereas the former group represents lysosome-like particles from muscle cells.
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PMID:Lysosomes in skeletal muscle tissue. Zonal centrifugation evidence for multiple cellular sources. 432 73

Homogenates of cultured rat embryo fibroblasts have been assayed for acid phosphatase, N-acetyl-beta-glucosaminidase, cathepsin D, acid deoxyribonuclease, cytochrome oxidase, NADH cytochrome c reductase, 5'-nucleotidase, inosine diphosphatase, acid pyrophosphatase, neutral pyrophosphatase, esterase, catalase, cholesterol, and RNA. The validity of the assay conditions was checked. Neutral pyrophosphatase is a readily soluble enzyme. Acid hydrolases, except acid pyrophosphatase, are particle-bound enzymes, which exhibit a high degree of structural latency. They are activated and solubilized in a parallel fashion by mechanical treatments and tensio-active agents. Catalase is also particle-bound and latent; activating conditions stronger than those for hydrolases are required to activate the enzyme. Acid pyrophosphatase, 5'-nucleotidase and inosine diphosphatase are firmly particle-bound, but not latent; they are not easily solubilized. In differential and isopycnic centrifugation, the latent hydrolases, cytochrome oxidase and catalase dissociate largely from each other; this suggests the occurrence of lysosomes and peroxisome-like structures besides mitochondria. The distribution patterns of 5'-nucleotidase and cholesterol are largely similar; digitonin influences their equilibrium density to the same extent; these two constituents are thought to be related to the plasma membrane. Inosine diphosphatase and acid pyrophosphatase are also partially associated with the plasma membrane, although some part of these enzymic activities probably belongs to other structures. NADH cytochrome c reductase is associated partly with the endoplasmic reticulum, partly with mitochondria.
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PMID:Analytical fractionation of homogenates from cultured rat embryo fibroblasts. 437 90

Young rats, fed a low calcium and vitamin D deficient diet for 2 weeks, developed hypocalcemia, an increased activity of serum alkaline phosphatase and an increase in the serum concentration of immunoreactive parathyroid hormone. An increased activity of lactate dehydrogenase and cytochrome oxidase in odontoblasts was found. No shift in the general energy metabolic pathway was found as visualized in the lactate dehydrogenase iso-enzyme pattern. The dominating lactate dehydrogenase isoenzyme in odontoblasts from both the normal and the deficient rats was LDH 1 (H4, LD5), thus indicating primarily an aerobic energy-metabolism Also the activities of the lysosomal enzymes acid phosphatase, cathepsin D and hyaluronidase in the odontoblasts from the deficient animals were increased when compared to the normal animals. No significant change could be demonstrated for beta-glucuronidase and beta-N-acetylglucosaminidase. It was earlier found that this deficient diet caused an increase in odontoblast alkaline phosphatase activities and protein synthesis in vitro. In view of the present findings it might be concluded that the low calcium and vitamin D deficient diet causes a general increase in the odontoblast metabolism. It is not known whether this is due to the increase in parathyroid hormone or if it is a direct effect of the lowered serum calcium concentration.
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PMID:Odontoblast metabolism in rats deficient in vitamin D and calcium. IV. Lysosomal and energy metabolic enzymes. 625 18

Previously we indicated that a specific delay in subunit c degradation causes the accumulation of mitochondrial ATP synthase subunit c in lysosomes from the cells of patients with the late infantile form of neuronal ceroid lipofuscinosis (NCL). To explore the mechanism of lysosomal storage of subunit c in patient cells, we investigated the mechanism of the lysosomal accumulation of subunit c both in cultured normal fibroblasts and in in vitro cell-free incubation experiments. Addition of pepstatin to normal fibroblasts causes the marked lysosomal accumulation of subunit c and less accumulation of Mn(2+)-superoxide dismutase (SOD). In contrast, E-64-d stimulates greater lysosomal storage of Mn(2+)-SOD than of subunit c. Incubation of mitochondrial-lysosomal fractions from control and diseased cells at acidic pH leads to a much more rapid degradation of subunit c in control cells than in diseased cells, whereas other mitochondrial proteins, including Mn(2+)-SOD, beta subunit of ATP synthase, and subunit i.v. of cytochrome oxidase, are degraded at similar rates in both control and patient cells. The proteolysis of subunit c in normal cell extracts is inhibited markedly by pepstatin and weakly by E-64-c, as in the cultured cell experiments. However, there are no differences in the lysosomal protease levels, including the levels of the pepstatin-sensitive aspartic protease cathepsin D between control and patient cells. The stable subunit c in mitochondrial-lysosomal fractions from patient cells is degraded on incubation with mitochondrial-lysosomal fractions from control cells. Exchange experiments using radiolabeled substrates and nonlabeled proteolytic sources from control and patient cells showed that proteolytic dysfunction, rather than structural alterations such as the posttranslational modification of subunit c, is responsible for the specific delay in the degradation of subunit c in the late infantile form of NCL.
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PMID:Specific delay in the degradation of mitochondrial ATP synthase subunit c in late infantile neuronal ceroid lipofuscinosis is derived from cellular proteolytic dysfunction rather than structural alteration of subunit c. 885 53

Chronic administration of Senna occidentalis seeds induces an experimental toxic myopathy characterized by skeletal muscle fibers atrophy, decrease in histochemical activity of cytochrome oxidase, and increase of the acid phosphatase activity in muscle fibres at the light microscopic level. The mechanisms that lead to the increase of this lysosomal enzyme activity are not known and could be related to other biochemical disturbs than the mitochondrial function impairment. The main aim of the present study is to localize the acid phosphatase activity using a cytochemical method at transmission electron microscopy level and to quantify cathepsin D in muscle of rats chronically intoxicated with Senna occidentalis seeds by immunoblotting. Acid phosphatase was observed in lysosomes and over profiles of some organelles apparently not involved by lysosomal membrane. In addition immunoblotting demonstrated a decrease in the content of the precursor and of the mature form of cathepsin D in samples of muscles and liver of intoxicated animals. We concluded that there is a selective increase in acid phosphatase activity in muscle--and maybe in other tissues--of animals intoxicated with Senna occidentalis, that can be related to the skeletal muscle atrophy and the intense decrease in weight gain of these animals. Further studies should be performed to establish the mechanisms of selectivity in increase of lysosomal enzymes in different situations and pathological states.
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PMID:The lysosomal enzymes acid phosphatase and cathepsin D in rats intoxicated with Senna occidentalis seeds. 1045 11

Differential centrifugation and density gradient isopycnic centrifugation have been used to fractionate homogenates of rat spleen and, in a few experiments, of rat thymus and cervical lymph nodes. The fractions have been analyzed for proteins, DNA, RNA, cytochrome oxidase, esterase, and up to 11 acid hydrolases. The results obtained indicate that the hydrolases are associated, at least largely, with cytoplasmic particles of lysosomal nature, and suggest further that these particles belong to two, and possibly three, distinct populations, perhaps reflecting the cellular heterogeneity of the tissues. The populations are identified as: (a) the L(19) population, the most important group, containing all 12 hydrolases and characterized by a modal density of about 1.19 in a sucrose-0.2 M KCl gradient; (b) the L(15) population with a modal density of 1.15, a group of apparently incomplete lysosomes containing cathepsin D and a few other enzymes, but very poor in, or entirely devoid of, several acid hydrolases, including cathepsins B and C; (c) the L(30) population, comprising all 12 enzymes and banding together with the nuclei at a density of 1.30 or higher. Lack of success in separating the latter group from the nuclei renders its significance unclear.
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PMID:Lysosomes in lymphoid tissue. II. Intracellular distribution of acid hydrolases. 1097 26

Stable overexpression of endothelial nitric oxide synthase (NOS-3) in HepG2 cells (4TO-NOS) leads to increased nitro-oxidative stress and upregulation of the cell death mediators p53 and Fas. Thus, NOS-3 overexpression has been suggested as a useful antiproliferative mechanism in hepatocarcinoma cells. We aimed to identify the underlying mechanism of cell death induced by NOS-3 overexpression at basal conditions and with anti-Fas treatment. The intracellular localization of NOS-3, the nitro-oxidative stress and the mitochondrial activity were analysed. In addition, the protein expression profile in 4TO-NOS was screened for differentially expressed proteins potentially involved in the induction of apoptosis. NOS-3 localization in the mitochondrial outer membrane was not associated with changes in the respiratory cellular capacity, but was related to the mitochondrial biogenesis increase and with a higher protein expression of mitochondrial complex IV. Nitro-oxidative stress and cell death in NOS-3 overexpressing cells occurred with the expression increase of pro-apoptotic genes and a higher expression/activity of the enzymes adrenodoxin reductase mitochondrial (AR) and cathepsin D (CatD). CatD overexpression in 4TO-NOS was related to the apoptosis induction independently of its catalytic activity. In addition, CatD activity inhibition by pepstatin A was not effective in blocking apoptosis induced by anti-Fas. In summary, NOS-3 overexpression resulted in an increased sensitivity to anti-Fas induced cell death, independently of AR expression and CatD activity.
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PMID:Sensitivity to anti-Fas is independent of increased cathepsin D activity and adrenodoxin reductase expression occurring in NOS-3 overexpressing HepG2 cells. 2571 67


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