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)

Proteolytic activities in bovine adrenocortical mitochondria were investigated using [14C-methyl]casein as a substrate. Washed mitochondria showed a low proteolytic activity at pH 7.5 or 8.2. ATP (5 mM) plus MgCl2 (7.5 mM) stimulated the proteolysis 9 times at pH 8.2. It was further demonstrated unequivocally by various approaches that the ATP-dependent proteolytic activity localizes in mitochondrial matrix. The activity of the solubilized protease was sensitive to N-ethylmaleimide, mersalyl acid, phenylmethylsulfonyl fluoride, o-vanadate, m-vanadate, vanadyl sulfate, and quercetin but not by oligomycin and ouabain. The ATP-dependent proteolytic activity was eluted at the position of 650,000 daltons on an Ultrogel AcA 22 column as a single symmetrical peak. The gel-filtered enzyme showed high specificity to ATP. GTP and UTP partially substituted ATP. ADP, AMP, tripolyphosphate, alpha, beta-methylene ATP, and beta, gamma-methylene ATP had little or no stimulating activity. ATP did not stimulate the activity in the absence of MgCl2. We measured ATP-dependent proteolytic activities in mitochondrial fractions from several tissues in rat and bovine. Adrenal cortex was one of the tissues of highest activity. In addition, we investigated the effect of adrenal atrophy on the ATP-dependent protease activity in rat adrenal. The ATP-dependent protease activity/adrenal decreased by dexamethasone treatment. The extent of the decrease was similar to that of cytochrome oxidase and succinate dehydrogenase, but smaller than that of cytochrome P-450.
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PMID:ATP-dependent protease in bovine adrenal cortex. Tissue specificity, subcellular localization, and partial characterization. 298 96

The catalytic activity and molecular aspects of Thiobacillus novellus cytpchrome c oxidase were affected by ATP. The steady-state kinetics in the oxidation of ferrocytochrome c by the oxidase varied with the presence or absence of ATP; the [S]-v curve of the reaction was sigmoid in the absence of ATP whereas it was a Michaelis-Menten-type hyperbola in the presence of 700 microM ATP. The oxidase was a dimer of the minimal structural subunit consisting of one molecule each of two subunits in the presence of Tween 20 and in the absence of ATP. The dimer dissociated into monomers in the presence of 700 microM ATP. The trough at 452 nm seen in the second derivative absorption spectrum of the CO compound of the oxidase in the absence of ATP, a characteristic of the cytochrome a component of cytochrome aa3, dissappeared in the presence of 700 microM ATP. However, ADP, AMP, GTP, CTP and UTP had little affect on both the [S]-v curve and the molecular mass of the oxidase when used in place of ATP.
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PMID:The effects of several nucleotides on the molecular state and catalytic activity of Thiobacillus novellus cytochrome c oxidase. ATP affects the oxidase uniquely. 1049 Nov 45

Alpha-synuclein (alpha-Syn) is enriched in nerve terminals. Two mutations in the alpha-Syn gene (Ala53--> Thr and Ala30--> Pro) occur in autosomal dominant familial Parkinson's disease. Mice overexpressing the human A53T mutant alpha-Syn develop a severe movement disorder, paralysis, and synucleinopathy, but the mechanisms are not understood. We examined whether transgenic mice expressing human wild-type or familial Parkinson's disease-linked A53T or A30P mutant alpha-syn develop neuronal degeneration and cell death. Mutant mice were examined at early- to mid-stage disease and at near end-stage disease. Age-matched nontransgenic littermates were controls. In A53T mice, neurons in brainstem and spinal cord exhibited large axonal swellings, somal chromatolytic changes, and nuclear condensation. Spheroid eosinophilic Lewy body-like inclusions were present in the cytoplasm of cortical neurons and spinal motor neurons. These inclusions contained human alpha-syn and nitrated synuclein. Motor neurons were depleted (approximately 75%) in A53T mice but were affected less in A30P mice. Axonal degeneration was present in many regions. Electron microscopy confirmed the cell and axonal degeneration and revealed cytoplasmic inclusions in dendrites and axons. Some inclusions were degenerating mitochondria and were positive for humanalpha-syn. Mitochondrial complex IV and V proteins were at control levels, but complex IV activity was reduced significantly in spinal cord. Subsets of neurons in neocortex, brainstem, and spinal cord ventral horn were positive for terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling, cleaved caspase-3, and p53. Mitochondria in neurons had terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling-positive matrices and p53 at the outer membrane. Thus, A53T mutant mice develop intraneuronal inclusions, mitochondrial DNA damage and degeneration, and apoptotic-like death of neocortical, brainstem, and motor neurons.
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PMID:Parkinson's disease alpha-synuclein transgenic mice develop neuronal mitochondrial degeneration and cell death. 1639 71