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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The metabolic effects of p-aminophenol have been compared with those of paracetamol and other analgesics in studies of rat liver and kidney in vitro. 2. p-Aminophenol injected into rats inhibited gluconeogenesis from lactate in renal cortical tubules, but not in isolated hepatocytes, and reduced kidney ATP content without affecting the ATP content of liver. Perfused kidneys from rats previously injected with p-aminophenol showed a 50% reduction of ATP content, severe inhibition of Na+ reabsorption and reduction of inulin clearance without significant inhibition of gluconeogenesis from lactate. 3. Paracetamol, p-phenetidine, phenazone and aspirin, when given intravenously to rats, had no effect on renal tubular glucose synthesis from lactate or pyruvate. Paracetamol and aspirin both slightly inhibited renal glucose synthesis from several different substrates when added directly to tubules. 4. Paracetamol (4 mmol/l) inhibited glucose synthesis from lactate and other substrates by 50% or more in isolated hepatocytes. Glucose synthesis from lactate was inhibited 30% by concentrations of paracetamol as low as 0.5 mmol/l. 5. These results indicate that p-aminophenol is a potent inhibitor of proximal tubular function, with its main site of action the inhibition of ATP synthesis and energy production, and they confirm the primary hepatotoxic effect of paracetamol.
Clin Sci Mol Med 1977 Nov
PMID:Effects of analgesics and related compounds on renal metabolism in rats. 58 32

Fragments of rat liver mitochondrial DNA were isolated. In vivo these fragments were able to form the complexes with the proteins of inner mitochondrial membrane. The fragments represent unique DNA regions with the secondary structure, their A-T content being equal to 82%. With the aid of phosphomonoesterase, polynucleotidkinase and gamma-(32P)-ATP mtDNA fragments were labeled and analyzed for oligopyrimidine composition. It was shown that they were enriched in di- and tri-oligo-pyrimidine blocks. The fragments are shown to form in vitro a complex with the membrane proteins. A single protein m. wt. 40,000) was reisolated from the complex.
Mol Biol (Mosk)
PMID:[Isolation and characteristics of DNA fragments bound to mitochondrial membrane proteins]. 61 37

1. Adaptive mechanisms of oxygen transport by blood have been studied in severely anaemic young patients on maintenance haemodialysis, in conditions of hyperphosphataemia (Pi greater than or equal to 2.2 mmol/l) or normophosphataemia. 2. In hyperphosphataemia whole-blood affinity for oxygen was slightly decreased, as measured by an increase in P50 (the partial pressure of oxygen necessary to half saturate haemoglobin). 2,3-Diphosphoglycerate was increased by 10% (P less than 0.10) whereas Pi, total erythrocyte phosphate and ATP were increased by 100%, 47% and 36% respectively, compared with control values. 3. After correction of hyperphosphataemia a small but significant decrease in P50 and 2,3-diphosphoglycerate, to normal values, was observed whereas the other variables, although significantly lowered, remained above control values. 4. In these severely anaemic and hyperphosphataemic patients P50 and 2,3-diphosphoglycerate are only slightly increased. ATP synthesis appears to be favoured over that of 2,3-diphosphoglycerate. This is possibly due to alterations in the erythrocyte membrane elicited by bi-weekly extracorporeal circulation. Adequate oxygen transport can be achieved only through a drastic increase in blood flow. Correction of hyperphosphataemia adds further to the abnormality. It is concluded that this condition could induce a long-term myocardial fatigue, which might be prevented with occasional small blood transfusions.
Clin Sci Mol Med 1978 Jan
PMID:Oxygen transport in children on maintenance haemodialysis. 62 Apr 97

The quantum yield of noncyclic photophosphorylation in chloroplasts excited by a series of 8 mus flashes of the saturating intensity displays a two-fold decrease when the flash-frequency is reduced from about 1.1 to about 0.8 s-1, whereas further decrease of flash frequency does not affect the average ATP yield per flash. Under excitation by two-flashes series the ATP yield is also about half-maximal. These observations are inconsistent with the concept postulating accumulation of energy contributions from several parallel or consecutive one-electron transfers as a prerequisite for ATP formation. The two-state model of a thylakoid membrane and of a coupling site is put forward according to which only one of these states ensures ATP formation in response to one electron transfer through one coupling site, whereas the other state is nonphosphorylating.
Mol Biol (Mosk)
PMID:[Efficiency of photophosphorylation in chloroplasts with steady and pulsed illumination]. 63 81

A new molecular mechanism of muscle contraction is considered based on the cyclochelate oxyphosphorane structure of the long-lived intermediate in myosin-catalyzed ATP. Mg hydrolysis proposed earlier by the author. The mechanism implies the steric cleavage of the actomyosin bond by the gamma-phosphoryl group of ATP.Mg tightly binding to myosin; the myosin-catalyzed addition of water to the gamma-phosphoryl group to give oxyphosphorane group which sterically allows the formation of a more weak bent (deformed) actomyosin bond; the actin-catalyzed breakdown of the tightly bound oxyphosphorane intermediate into weakly bound products; the straightening of the bent actomyosin bond with the active change of an angle of myosin head attachment, the liberation of the weakly bound products and the displacement of the actin filament. The data are given in favour of an oxyphosphorane structure of the long-lived intermediate.
Mol Biol (Mosk)
PMID:[Molecular mechanism of muscle contraction: the straightening of the bent actomyosin bond]. 73 89

Ca2+-entry into intact red cells containing [32P]-ATP increases the phosphorylation of the 150 000 dalton polypeptide of the membrane. This phosphorylation occurs even in Mg2+-depleted red cells. Extracellular lanthanum applied during ATP-depletion further increases the Ca2+-induced phosphorylation. In fragmented membranes or resealed insideout vesicles (IOVs) membrane bound Mg2+ is sufficient to catalyze the phosphorylation of spectrin 2 and Band 3 polypeptides with low concentrations (less than micron of [32P]-ATP. In Ca-EDTA buffers one single polypeptide is phosphorylated which is located in the 150 000 molecular weight region. KmCa for phosphorylation is much lower (0.2 micron) than for active Ca2+ transport (40 micron) in IOVs. Lanthanum induced phosphorylation (up to 250 micron Lafree) is significantly greater than Ca2+-induced phosphorylation. Hg2+ inhibits both Ca2+ and La3+ induced phosphorylation. Ca2+-induced labelling can be rapidly "chased" by unlabelled ATP+Mg2+, but not with EGTA+Mg2+. Dephosphorylation in Ca2+ phosphorylated membranes and IOVs is significantly inhibited by La3+. It can be concluded that the mechanism of La3+ and Hg2+ inhibition of the Ca2+ pump is different in intact cells and isolated membranes or Iovs.
Mol Cell Biochem 1978 Dec 22
PMID:Phosphorylation of the Ca2+ pump intermediate in intact red cells, isolated membranes and inside-out vesicles. 74 97

Gluconeogenesis by isolated hepatocytes resulted in glucose release but insignificant rates of glycogen synthesis. The effectiveness of precursors was similar for hepatocytes from fed and starved chickens except for impaired gluconeogenesis from pyruvate when compared to lactate in lactate starved chicken hepatocytes. The impairment was caused by limitations in cytosolic NADH production as a result of the mitochondrial location of phosphoenolpyruvate carboxykinase in chicken liver. The order of effectiveness of precursors on hepatic gluconeogenesis was generally similar to the effects of precursors on increasing the plasma glucose concentration in vivo. The exceptions were caused by interactions with other precursors in vivo. The alteration of the NADH/NAD+ ratio by ethanol and ATP/ADP ratio by adenosine could play significant roles in the control of precursor conversion to glucose. Physiological glucagon concentrations stimulated gluconeogenesis from precursors entering the pathway both above and below the level of triose phosphates, and its effect were mimicked by dibutyryl cyclic AMP. Previous results on the effects of precursor and glucagon injection on the plasma glucose concentration of chickens in vivo can largely be explained by effects at the hepatic level. Isolated chicken and rat hepatocytes share many common features. Qualitatively the ordering of gluconeogenic effectiveness was similar but quantitive differences existed as a result of differing activities and cellular locations of enzymes. Neither preparation readily synthesised glycogen and the sensitivity to glucagon was similar.
Mol Cell Biochem 1978 Dec 22
PMID:Hepatic gluconeogenesis in chickens. 74 98

A mechanism responsible for proteolytic deproteinization of influenza virus A2 Hong-Kong (I)68 by plasmatic membranes of sensitive cells was studied. Presence of trypsinlike protease in plasmatic membranes of white mice lungs was demonstrated. A considerable inhibition of the membrane proteolitic activity was obtained in the presence of epsilon-aminocaproic acid. Disintegration of the virus labeled by [3H]uridine by plasmatic membranes was investigated and it was found that this process required ATP. Inhibition of the protease activity by epsilon-aminocaproic acid led to the suppression of deproteinization of influenza virus. The experimental data obtained indicate that the proteolytic enzymes of plasmatic membranes participate in the complex process of virus "uncoating".
Mol Biol (Mosk)
PMID:[Proteolytic mechanism of deproteinization of influenza virus by plasmatic membranes]. 75 90

We estimate that E. coli RNA polymerase is able to form stable, rifampicin-resistant, pre-intiation complexes with Adenovirus 2 DNA at three to six binding sites. The number of RNA chains initiated from such complexes has been determined form the incorporation of gamma-32P-ATP and -GTP at two rifampicin concentrations (7 mug/ml and 24 mug/ml) and after pre-incubation at either 25 or 37 degrees C. The total number of RNA chains initiated ranges from 2.6 per Ad 2 DNA molecule at a rifampicin concentration of 24 mug/ml and pre-incubation temperature of 25 degrees C, to 5.4 per Ad 2 DNA molecule at a rifampicin concentration of 7 mug/ml and pre-incubation temperature of 37 degrees C. Efficient initiation with GTP occurs only after pre-incubation at 37 degrees C whereas initiation with ATP is equally as efficient at either pre-incubation temperature. Promoters for initiation with ATP have been localized to the leftmost 58% of the Ad 2 DNA molecule, defined by the EcoR.RI restriction endonuclease fragment A; promoters for initiation with GTP are located on the remaining 42% of the Ad2 DNA molecule. It is likely that on Adenovirus 2 DNA each RNA chain is initiated from a unique binding site which constitutes a seperate promoter for E. coli RNA polymerase.
Mol Gen Genet 1976 Jan 16
PMID:In vitro transcription of adenovirus 2 DNA. II. Quantification and localization of promoters for E. coli RNA polymerase. 76 52

The paper deals with the comparative investigation of initiation and in vitro RNA synthesis on DNA template by E. coli RNA polymerase and B-form of calf thymus RNA polymerase. It was shown in hybridization experiments that in the range of Cot values between 10(2) and 10(4) RNA synthesized by calf thymus RNA polymerase was hybridized with homologous DNA more effectively than RNA synthesized by E. coli RNA polymerase. No differences were observed in the case of low Cot values. RNA chains synthesized by calf thymus RNA polymerase contained in average about 300-600 nucleotides per chain as determined in the kinetic experiments with ATP-gamma-32P and GTP-gamma-32P. These values are in average 5-10 times lower than in the case of bacterial enzyme. The data presented show that calf thymus and E. coli RNA polymerases initiate the RNA synthesis at apparently different sites of calf thymus DNA. The results obtained make the possibility of specific transcription of eucaryotic DNA by bacterial RNA polymerase to be doubtful.
Mol Biol (Mosk)
PMID:[Transcription of DNA by RNA polymerases of E. coli and calf thymus]. 76 44


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