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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chicken embryo cells infected with the HEP Flury strain of rabies virus adapted to tissue culture produced a hemadsorption (HAD) phenomenon by using goose erthyrocytes. The optimal conditions for HAD included the incubation of cell cultures at 37C for 3 days after virus inoculation, the use of a 0.4% suspension of goose erythrocytes in phosphate buffer adjusted at pH 6.2, and adsorption of erythrocytes at 4C. This phenomenon was inhibited with anti-rabies serum. Virus titer obtained with the HAD technique was almost the same as with the fluorescent antibody technique or the intracerebral inoculation of suckling mice. Results of the neutralization test by using the HAD technique could be easily determined 3 days after inoculation of chicken embryo cells with the mixture of 100 mean tissue culture infective doses of virus and diluted serum. The neutralizing antibody titers coincided with those obtained in mice.
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PMID:Use of the hemadsorption phenomenon for determining virus and neutralizing antibody titers of rabies. 5 27

The ATP-ADP exchange activity previously described in a membrane farction of Escherichia coli appeared after a cold osmotic shock according to Neu and Heppel ((1965) J. Biol. Chem. 240, 3685--3692) in the shock fluid. Membranes derived from shocked cells had no activity. The enzyme responsible for this activity has been purified 125-fold and catalyzed the transfer of a phosphoryl radical from ribonucleosidetriphosphates (NTPs) to ribonucleosidediphosphates (NDPs); this is, therefore, a non-specific nucleosidediphosphate kinase (ATP:nucleosidediphosphate phosphotransferase, EC 2.7.4.6). The activity required the presence of a divalent cation, Mg2+, Mn2+ or Ca2+ at a unity mol/mol ratio of nucleotide for maximal activation. The enzyme exhibited simple saturation kinetics with respect to the phosphate donor but inhibition by excess substrate was observed upon increasing phosphate acceptor. The kinetics of the reaction indicated an ordered bi-molecular ping-pong reaction mechanism. Differential heat sensitivity of the enzyme whether it is heated alone with ATP, ADP or Mg2+ opens possibilities to study different enzyme-substrate complexes.
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PMID:Nucleosidediphosphate kinase of Escherichia coli, a periplasmic enzyme. 21 26

The lipid composition of highly purified Flury strain of rabies virus (HEP) propagated in BHK-21 cells in a chemically defined medium was observed to be 6.7% neutral lipids, 15.8% phospholipids, and 1.5% glycolipids. In the virion, phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin were the most abundant phospholipids, accounting for 90% of the total, and the molar ratio of cholesterol to phospholipid was 0.48. Uninfected BHK-21 cell membranes were obtained by nitrogen cavitation techniques and separated by density gradient centrifugation, and the membranes were assayed for purity using 5'-nucleotidase, cytochrome oxidase, and reduced nicotinamide adenine dinucleotide phosphate diaphorase activities. Lipids of the plasma membrane were enriched in cholesterol, phosphatidylcholine, and phosphatidylethanolamine. In contrast, membranes of the endoplasmic reticulum were enriched in phosphatidylcholine, but contained smaller amounts of phosphatidylethanolamine and sphingomyelin. Comparison of the fatty acyl chains of virus and membranes from uninfected cells revealed the virion to have the lowest ratio of C18:1 to C18:0 (1.771), compared with values of about 3.0 for the plasma membrane and endoplasmic reticulum. Total polyenoic fatty acids were enriched in the plasma membrane, whereas the virus contained higher amounts of total saturates than either of the two membrane preparations. Analysis of the polar and neutral lipid fractions as well as the acyl chain analysis suggests the virion has a lipid composition that is intermiediate to that of the plasma membrane and endoplasmic reticulum and is consistent with the view that numerous viral particles are synthesized de novo by not utilizing a preexisting membrane template. From the ratio of cholesterol to phospholipid of 0.48, we calculated that 1.92 X 10(5) molecules of lipid would cover 4.14 X 10(4) nm2 in the form of a bilayer. Considerations of the molecular dimensions of the rabies envelope (total surface area, 5 X 10(4) nm2) as a bilayer suggest that some penetration of lipids by envelope proteins (M and G) is necessary.
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PMID:Lipids of rabies virus and BHK-21 cell membranes. 55 73

Because of premature labour, probability of fetal retardation, discrepance at term of delivery, Rh-incompatibility or EPH-gestosis 185 patients were hospitalized. 76 pregnant women received twice 1.5 ml Celestan Depot i.m. (4.5 betamethasone acetate and 6mg betamethasome dinatrium phosphate per injection) within an interval of 24 hours. It was necessary to maintain a tocolysis for at least 48 hours as a minimum after the first injection of Celestan Depot. The other 109 patients without treatment of glucocorticoids were considered as a controlgroup. We could show that antepartum application of betamethasone before the 38. week of gestation was associated with a reduction of RDS in our premature infants. Only one baby of the betamethasone-treated infants died of hyaline membrane disease during the first 7 days of life compared with 11 of the control group. In 11 patients patients amniocentesis was performed before the first injection of glucocorticoids and was repeated 2 to 7 days later. The amniotid fluid lecithin phosphorus concentration was determined. In the same period of pregnancy and the same iterval the lecithin phosphours level of amniotic fluid was analysed in 11 other patients who were not rreated with glucocorticoids. The difference between amniotic fluid lecithin phosphorus concentration in the first and second anslysis was found significant by a level of significance of alpha = 5%. There was no evidence of an influence of the therapy with Celestan Depot on this increase. The excretion of oestorgens in the urine of 24 hours was analysed in 22 gradidae before and 7 days after the treatment with betamethasone. The oestogen values of the day before application of betamethasone served as baseline figures. All patients showed a market fall in urinary oestrogens excretion, especially after the second day of therapy. After day 2 the values returned rapidly to baseline values. There were no differences between treated and control groups in Apgar scores at birth or in the incidence of icterus neonatroum (bilirubine level is greater that 10 mg% in the serum). The results of our study support the hypothesis that in humans glucocorticoid administration to the fetus accelerates lung maturation. Relatively brief intrauterine exposure of human infants to pharmacological doses of betamethasone was associated with a substantial reduction in the incidense of RDS.
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PMID:[First experiences with prenatal affection of infantile lung maturation by betamethason (author's transl)]. 115 18

Effects of 5 cold storage solution on hepatic high energy phosphate metabolism and metabolic function were examined using the isolated perfused rat liver. University of Wisconsin (UW), Euro-Collins (EC), and 2 cardioplegic solutions, Bretschneider's HTK and St. Thomas Hospital solution, were studied for their protective capacity. Krebs-Henseleit bicarbonate buffer (KHB) was used to point out the effect of simple hypothermia. Liver ATP, total adenine nucleotides and energy charge losses were significantly lower during 21 h of storage in UW-preserved livers. Also, only UW-protected livers were able to complete regeneration of ATP and total adenine nucleotides after 1 h of reperfusion, whereas EC, HTK, St. Thomas and KHB stored livers only showed minimal regeneration. Concerning metabolic function, UW protected livers liberated significantly less LDH and sGOT as well in the 21-hour storage solution as into the perfusate under reperfusion conditions. This study demonstrates the capability of UW solution in liver preservation by its ability to maintain and restore high energy phosphates.
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PMID:Hepatic energy metabolism during hypothermic storage and reperfusion using different protecting solutions. 129 38

Prostaglandin E2 (PGE2), PTH, and epidermal growth factor (EGF) are potent regulators of osteoblast proliferation. In UMR 106-01 rat osteosarcoma cells with osteoblast-like features, PGE2 and PTH inhibit, while EGF stimulates, mitogenesis. Both PGE2 and PTH increase intracellular cAMP levels, cytosolic calcium, and inositol phosphate turnover. In a variety of cell types, EGF mediates its effects in part via activation of receptor protein-tyrosine kinase and other protein kinases, such as protein kinase-C. The nuclear mechanisms of PGE2, PTH, and EGF regulation of osteoblast proliferation are unknown. Accordingly, we have examined the effects of these agents on mitogenesis, second messenger generation, and primary response genes, which may link second messenger activation to subsequent alterations in gene expression. Northern blot analysis of mRNA from UMR 106-01 cells treated for 3 h with 2 microM PGE2, 10 nM PTH, or 10 ng/ml EGF in the presence of cycloheximide demonstrated that all three agents induced the expression of c-fos and c-jun mRNA. In contrast, only EGF stimulated cellular proliferation and induced Egr-1 mRNA. Also, unlike PGE2 and PTH, EGF did not increase intracellular cAMP levels. c-fos mRNA was induced by treatment with 50 ng/ml tetradecanoyl phorbol acetate or by 40 ng/ml forskolin, while induction of Egr-1 mRNA was stimulated by treatment with tetradecanoyl phorbol acetate, but not forskolin. Thus, EGF signal transduction differs from that of PGE2 and PTH in UMR 106-01 osteoblast-like cells, in that EGF does not stimulate the protein kinase-A second messenger system, but causes activation of Egr-1, a primary response gene that may play a role in the mitogenic effect of EGF.
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PMID:The effects of prostaglandin E2, parathyroid hormone, and epidermal growth factor on mitogenesis, signaling, and primary response genes in UMR 106-01 osteoblast-like cells. 133 Apr 91

Tyrosine hydroxylase (TH) is phosphorylated at four sites in situ and in vivo, and the protein kinases that phosphorylate three of these sites (Ser8,Ser19,Ser40) have been identified. In intact cells, the phosphorylation of the fourth site (Ser31) is increased in response to phorbol esters or nerve growth factor (NGF). Here, we show that Ser31 is phosphorylated by ERK1 and ERK2, two myelin basic protein and microtubule-associated protein kinases. Extracts of NGF- or bradykinin-treated PC12 rat pheochromocytoma cells were fractionated on Mono Q columns. Protein kinase activity toward Ser31 in TH was present in two peaks corresponding to myelin basic protein kinase activities previously identified as ERK1 and ERK2. Phosphorylation of purified TH in vitro by both kinases was selective for Ser31 up to at least 0.6 mol of phosphate per mol of TH subunit. Treatment of intact PC12 cells with bradykinin or NGF increased both the phosphorylation of TH-Ser31 in situ and the catalytic activity of ERKs (measured subsequently in vitro with myelin basic protein as substrate). Pretreatment of the cells with genistein (a protein-tyrosine kinase inhibitor) decreased the bradykinin- but not the NGF-induced changes in both TH-Ser31 phosphorylation and ERK activity. Genistein also inhibited the increases in Ser31 phosphorylation produced by phorbol dibutyrate, muscarine, and Ba2+. The data indicate that ERK activity is responsible for phosphorylating TH at Ser31 in intact cells and suggest that TH-Ser31 phosphorylation may be regulated by multiple signaling pathways that converge at or prior to the activation of the ERKs.
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PMID:ERK1 and ERK2, two microtubule-associated protein 2 kinases, mediate the phosphorylation of tyrosine hydroxylase at serine-31 in situ. 134 49

The aim of our study was to test the effectiveness of two cardioplegic solutions and to compare the level of high energy phosphates in the myocardium. We investigated 18 hearts of pigs (obtained from a slaughter-house) with 31phosphorusmagnetic resonance spectroscopy (31P-MRS) In this experiment coronary arteries were cannulated and reperfused with arterial blood to revitalize the heart. When the heart showed regular pulsations coronary arteries were perfused for cardioplegia either with the UW-(Belzer-) or with the HTK-(Bretschneider-)solution. For 31P-MRS, a magnet with a magnetic flux density of 4.7 Tesla (T) was available. Relative concentrations from phosphocreatine (PCr/beta-ATP; high-energy phosphate) and inorganic phosphate (Pi/MDP; MDP = methylendiphosphonat = reference solution; low-energy phosphate) were calculated from the spectra. As a result of this study, the HTK-solution showed a significantly higher PCr/beta-ATP-ratio in the myocardium than the UW-solution during the examination time of 3 h. After plegia of the myocardial area from the right coronary artery PCr/beta-ATP-ratios were lower in comparison with the left coronary artery distribution area. The calculation of Pi/MDP-ratios proved that Pi was higher in the myocardium after application of the UW-solution compared to HTK-solution. The kinetics of the metabolites showed an approximately linear and parallel decrease of PCr/beta-ATP-ratios after cardioplegia with both solutions during the examination time.
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PMID:[The effect of Belzer and Bretschneider cardioplegia solutions on myocardial energy metabolism. A study with 31phosphorus magnetic resonance spectroscopy in an animal model]. 149 55

Embryonal carcinoma (EC) cells are the malignant stem cells of teratocarcinoma and have the capacity to proliferate in the absence of serum growth factors. As yet no receptor protein tyrosine kinases have been identified on undifferentiated EC cells and as a consequence tyrosine kinase signaling pathways could not be studied in these cells. We have used stably transfected P19 embryonal carcinoma cells expressing a well-characterized receptor protein tyrosine kinase, the human epidermal growth factor receptor (hEGF-R) to study protein tyrosine kinase signaling mechanisms in undifferentiated EC cells. Here we report that the ectopically expressed hEGF-R contains EGF-inducible autophosphorylation activity and is rapidly internalized and degraded upon ligand binding. In addition, the exogenous hEGF-R confers EGF-responsiveness to these cells in that inositol phosphate formation and cytoplasmic-free Ca2+ concentration are enhanced in response to EGF. Furthermore, the Na+/H+ exchanger is activated in response to EGF, leading to a sustained rise in intracellular pH. Our results show that undifferentiated P19 EC cells contain the necessary components of protein tyrosine kinase signal transduction machinery.
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PMID:Characterization of a tyrosine kinase signaling pathway in undifferentiated P19 embryonal carcinoma cells. 165 71

Several steps implicated in platelet-derived growth factor (PDGF) receptor-coupled signaling are activated by PDGF exposure at 0-4 degrees C. These include receptor self-phosphorylation, physical association with and phosphorylation of phospholipase C gamma (PLC gamma). Reduced temperature blocks PDGF internalization, making it possible to dissociate bound PDGF after PLC gamma tyrosine phosphorylation. We addressed the functional consequences of PDGF dissociation from intact cell PDGF receptors. PDGF exposure at 0-4 degrees C for 15 min stimulated self-phosphorylation of a subpopulation of BALB/c 3T3 cell PDGF beta-type receptors (35%) and initiated subsequent inositol phosphate production. A small fraction of cellular PLC gamma (1-3%) coprecipitated with ligand-activated PDGF receptors; 3-5% of cellular PLC gamma acquired phosphotyrosine. The PLC gamma coprecipitating with PDGF receptors did not contain detectible phosphotyrosine. Phosphotyrosine antibody recovered similar amounts of PLC gamma from soluble and particulate fractions of PDGF-stimulated cells. Acid dissociation of bound PDGF from receptor caused rapid dephosphorylation of PDGF receptors and PCL gamma, and interrupted PLC gamma-PDGF receptor coprecipitation. Orthovanadate blocked tyrosine dephosphorylation of both PDGF receptors and PLC gamma and stabilized coprecipitation. Orthovanadate reversed the acid wash effect to abrogate PDGF-stimulated inositol phosphate production. PDGF receptor remains competent to coprecipitate with PLC gamma and stimulate PLC-mediated inositol phosphate production if PDGF-induced receptor phosphorylation is maintained. Formation of a coprecipitable PDGF receptor-PLC gamma complex appears required for PDGF-stimulated inositol phosphate production.
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PMID:Phospholipase C gamma complexes with ligand-activated platelet-derived growth factor receptors. An intermediate implicated in phospholipase activation. 184 94


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