[Determining phosphopyruvic acid in the blood of sick animals].
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Animals↗
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Results for “PHOSPHOPYRUVIC ACID”
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[Enzymatic localization in the sub-mitochondrial fractions of pigeon liver. I. Study of glutamic dehydrogenase, isocitrate dehydrogenase (NADP), the enzymes of fatty acid synthesis and phosphopyruvic carboxylase].
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Animals↗
Intermediates in photosynthesis.
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Carbon Dioxide↗
Evidence that stimulation of gluconeogenesis by fatty acid is mediated through thermodynamic mechanisms.
We have studied the stimulatory effects of palmitate on the rate of glucose synthesis from lactate in isolated hepatocytes. Control of the metabolic flow was achieved by modulating the activity of enolase using graded concentrations of fluoride. Unexpectedly, palmitate stimulated gluconeogenesis even when enolase was rate-limiting. This stimulation was also observed when the activities of phosphoenolpyruvate carboxykinase and aspartate aminotransferase were modulated using graded concentrations of quinolinate and aminooxyacetate, respectively. Linear force-flow relationships were found between the rate of gluconeogenesis and indicators of cellular energy status (i.e. mitochondrial membrane and redox potentials and cellular phosphorylation potential). These findings suggest that the fatty acid stimulation of glucose synthesis is in part mediated through thermodynamic mechanisms.
Aminooxyacetic Acid↗
[Diagnostic value of biochemical tumor markers in brain tumors. Review of the literature and own experience with serum analysis of sialic acid (NANA), carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE)].
In a review of the literature the current knowledge of the diagnostic significance of sialic acid (NANA), neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA) in the detection and differentiation of brain tumors is demonstrated. The efficiency of some additional biochemical tumor markers is briefly described. In a total of 101 patients of our own 63 patients operated on intracranial expansive lesions and 38 patients with non-tumoral diseases of the central nervous system were examined for their serum concentrations of NANA, NSE and CEA with additional determination of total serum protein (TSP) and C-reactive protein (CRP) concentrations. 24 benign, 15 semibenign, 12 semimalign and 12 malign expansions were compared with each other and with the controls for their tumor marker concentrations. The criteria of the diagnostic reliability (sensitivity, specificity, positive and negative predictive value) were calculated for each single marker and the reliability of information for the combined used markers was evaluated. In summary the following results were found: The concentration of C-reactive protein corresponded significantly with the NANA-concentrations on the one hand and with the CEA-concentrations on the other hand (p less than 0.05). NANA: 1. The average concentration increased with increasing malignancy (no significance). 2. Patients who suffered from non-tumorous diseases of the central nervous system which coincided with brain tissue lesions had often extremely high values. 3. 4 of 10 healthy controls had NANA-levels above the reference value. 4. The sensitivity was 44%, the specificity 73%, the positive predictive value 17%, the negative predictive value 88% (patients with pathological CRP- or TSP-values excluded).(ABSTRACT TRUNCATED AT 250 WORDS)
Biomarkers, Tumor↗
Contrary effect of lactic acid on expression of neuron-specific enolase and glial fibrillary acidic protein in human glioma cells.
We examined the effect of lactic acid on cultured human glioma cell lines expressing glial fibrillary acidic protein (GFAP), vimentin and neuron-specific enolase (NSE). The growth of the cells was inhibited by the lactic acid in a dose-dependent manner. At 56 mM of lactic acid, the surviving cells of the KNS-42-c2 cell line developed slender processes and increasingly formed bizzar giant cells. In an immunofluorescence study of the lactic acid-resistant cells, the GFAP-positive cells prominently decreased in number, while the NSE-positive cells clearly increased. The vimentin was not affected throughout the experiment. After removing lactic acid from the medium, the GFAP-positive cells gradually increased in number. The method of dot immunoassay was useful for quantifying GFAP in cellular extracts. It indicated that the amount of GFAP decreased in the cells cultured with lactate-containing media and increased to the primary values after removing the lactic acid. These results may suggest that the morphological and immunochemical diversities of glioma cells are secondarily affected by cellular microenvironments such as lactic acid.
Cell Line↗
Okadaic acid induced cyclin B1 expression and mitotic catastrophe in rat cortex.
Accumulating evidence indicates that the aberrant re-entry of post-mitotic neurons into the G2/M phase of cell cycle and the resulting mitotic catastrophe may contribute to the pathogenesis of Alzheimer's disease. However, the cellular event that drives the differentiated neurons to abnormally enter G2/M phase remains elusive. Similarly, whether mitotic catastrophe is indeed one of the death pathways for differentiated neurons is not clear. Previous studies revealed that okadaic acid (OA), a phosphatase inhibitor that induces AD like pathological changes, evokes mitotic changes in neuroblastoma cells. In this study, we examined the in vivo effects of OA on cyclin B1 expression, the induction of mitosis, and subsequent mitotic catastrophe. We found that cyclin B1 expression in adult neurons was significantly increased after injecting OA into rat frontal cortex, which also increased tau protein phosphorylation. Interestingly, cyclin B1 and phosphorylated tau were well co-localized around the OA injection site, but were only partially co-localized in other brain regions. Staining with toluidine blue, Giemsa dye or propidium iodide revealed typical mitotic and mitotic catastrophe-like morphological changes with irregular arrangement of condensed chromatin and chromosome fibers in a few cells. Furthermore, the strong cyclin B1 staining in these cells suggests that cyclin B1 promoted G2 to M phase transition is required for the mitotic catastrophe. The detection of neuron-specific enolase in a portion of these cells demonstrated that at least part them are neuron. All together, our results suggest that the disturbance of the protein kinase-phosphatase system caused by OA is sufficient to induce neuronal cyclin B1 expression, force neurons into the mitotic phase of cell cycle, and cause mitotic catastrophe.
Animals↗
A differential scanning calorimetric study of the effects of metal ions, substrate/product, substrate analogues and chaotropic anions on the thermal denaturation of yeast enolase 1.
The thermal denaturation of yeast enolase 1 was studied by differential scanning calorimetry (DSC) under conditions of subunit association/dissociation, enzymatic activity or substrate binding without turnover and substrate analogue binding. Subunit association stabilizes the enzyme, that is, the enzyme dissociates before denaturing. The conformational change produced by conformational metal ion binding increases thermal stability by reducing subunit dissociation. 'Substrate' or analogue binding additionally stabilizes the enzyme, irrespective of whether turnover is occurring, perhaps in part by the same mechanism. More strongly bound metal ions also stabilize the enzyme more, which we interpret as consistent with metal ion loss before denaturation, though possibly the denaturation pathway is different in the absence of metal ion. We suggest that some of the stabilization by 'substrate' and analogue binding is owing to the closure of moveable polypeptide loops about the active site, producing a more 'closed' and hence thermostable conformation.
Anions↗
Lactate attenuates neuron specific enolase elevation in newborn rats.
This study was undertaken to investigate the protective role of lactate on the hypoxic brain in newborn rats. A total of 107 7-day-old Wistar rats were divided into three groups. The lactate accumulation group was given 5% oxygen and 95% nitrogen for 30 minutes. The lactate elimination group was given 5% oxygen, a concentration of 7.5% carbon dioxide, and 87.5% nitrogen for 30 minutes. The control rats were placed in room air. Lactate levels in the brain tissue were higher in the lactate accumulation group than in those of the control group (control: 1.78 +/- 0.91, lactate accumulation: 11.42 +/- 1.64 mmol/kg) and significantly decreased in the lactate elimination group (4.10 +/- 1.73 mmol/kg). Blood pH remained at the same levels in the two groups. Neuron specific enolase in the cerebrospinal fluid, which is the initial neurocyte damage marker, was significantly elevated in the lactate elimination group (control: 18.3 +/- 7.5, lactate accumulation: 18.8 +/- 7.9, lactate elimination: 63.1 +/- 61.3 ng/mL). Brain adenosine 5'-triphosphate levels were significantly decreased in the lactate elimination group. Histologic findings of the brain at 72 hours after the load revealed no abnormal changes in any of the groups examined. The authors conclude that lactate accumulation plays a protective role on the hypoxic brain in newborn rats.
Adenosine Triphosphate↗
Proteomic identification of age-dependent protein nitration in rat skeletal muscle.
Age-related protein nitration was studied in skeletal muscle of Fisher 344 and Fisher 344/Brown Norway (BN) F1 rats by a proteomic approach. Proteins from young (4 months) and old (24 months) Fisher 344 rats and young (6 months) and old (34 months) Fisher 344/BN F1 animals were separated by 2-D gel electrophoresis. Western blot showed an age-related increase in the nitration of a few specific proteins, which were identified by MALDI-TOF MS and ESI-MS/MS. We identified age-dependent apparent nitration of beta-enolase, alpha-fructose aldolase, and creatine kinase, which perform important functions in muscle energy metabolism, suggesting that the nitration of such key proteins can be, in part, responsible for the decline of muscle motor function of the muscle. Furthermore, we have identified the apparent nitration of succinate dehydrogenase, rab GDP dissociation inhibitor beta (GdI-2), triosephosphate isomerase, troponin I, alpha-crystallin, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
Age Distribution↗
Markers of cerebral ischemia after cardiac surgery.
The objective of this review is to provide an overview of the use of biochemical markers for the detection of Central Nervous System (CNS) complications after cardiac surgery and extracorporeal circulation (ECC). A computerized literature search in MEDLINE from 1966 onward was the basis for the references. The literature covering the following biochemical markers is reviewed: adenylkinase, creatine phosphokinase isoenzyme BB (CK-BB), lactate, neuron-specific enolase (NSE), S-100 protein, myelin basic protein, lactate dehydrogenase, aspartate aminotransferase, glutathione, vasointestinal neuropeptide, and 7B2-specific neuropeptide. For clinical purposes, it is necessary to have a biochemical marker that can be measured in blood. Lactate, although a primary marker of anaerobic metabolism, and CK-BB values, calculated from the arterio-internal jugular venous difference, appear to correlate with periods of ischemia during ECC. S-100 protein levels have been shown to correlate with duration of ECC, and when combined with NSE values, could be used to identify patients with CNS dysfunction after cardiac surgery. The use of NSE may be limited by its presence in erythrocytes and platelets because the high levels that can result from hemolysis can render it less specific. Although recently introduced, S-100 protein may have the potential to be a valuable marker for CNS dysfunction after ECC.
Adenylate Kinase↗
Catalytic metal ion binding in enolase: the crystal structure of an enolase-Mn2+-phosphonoacetohydroxamate complex at 2.4-A resolution.
Enolase, a glycolytic enzyme that catalyzes the dehydration of 2-phospho-D-glycerate (PGA) to form phosphoenolpyruvate (PEP), requires two divalent metal ions per active site for activity. The first metal ion, traditionally referred to as "conformational", binds in a high-affinity site I. The second metal ion, "catalytic", binds in site II only in the presence of a substrate or substrate analogue and with much lower affinity for the physiological cofactor Mg2+. While the high-affinity site has been well characterized, the position of the lower affinity site has not been established so far. Here, we report the structure of the quaternary complex between enolase, the transition-state analogue phosphonoacetohydroxamate (PhAH), and two Mn2+ ions. The structure has been refined by using 16 561 reflections with F/sigma (F) > or = 3 to an R = 0.165 with average deviations of bond lengths and bond angles from ideal values of 0.013 A and 3.1 degrees, respectively. The "catalytic" metal ion is coordinated to two oxygen atoms of the phosphono moiety of PhAH and to the carbonyl oxygen of Gly37. Most likely, disordered water molecules complement its coordination sphere. The interaction with the site II metal ion must stabilize negative charge on the phosphate group and produce electron withdrawal from carbon 2 of the substrate, facilitating proton abstraction from carbon 2, the rate-limiting step in the catalytic process. The Gly37 residue is located in the flexible loop Ser36-His43, which assumes an "open" conformation in the absence of substrate and a "closed" conformation in the presence of a substrate.(ABSTRACT TRUNCATED AT 250 WORDS)
Binding Sites↗
Chelation of serine 39 to Mg2+ latches a gate at the active site of enolase: structure of the bis(Mg2+) complex of yeast enolase and the intermediate analog phosphonoacetohydroxamate at 2.1-A resolution.
The structure of a new crystal form of enolase from bakers' yeast has been solved to 2.1-A resolution. Crystals were grown from poly(ethylene glycol) and KCl at pH 8.2 in the presence of Mg2+ and a reaction intermediate analog, phosphonoacetohydroxamate (PhAH). Crystals belong to space group C2; have unit cell dimensions a = 123.5 A, b = 73.9 A, and c = 94.8 A with beta = 93.3 degrees; and contain one dimer per asymmetric unit. The structure was solved by molecular replacement from the X-ray coordinates of apoenolase [Stec, B., & Lebioda, L. (1990) J. Mol. Biol. 211, 235-248]. Both essential divalent metal ions are observed to be complexed with the inhibitor. The two Mg2+ ions are 4.05 A apart and are bridged by a mu-oxyl ligand from the carbonyl moiety of PhAH. The "high-affinity" Mg2+ coordinates to the carboxylate side chains of Asp 246, Glu 295, and Asp 320, one water molecule, and the hydroxamate and carbonyl oxygens of PhAH. The second Mg2+ coordinates to a phosphonyl oxygen, two water molecules, and the mu-bridge carbonyl oxygen of PhAH. Coordination schemes with respect to PhAH and water ligands are fully consistent with those of the Mn2+ complexes determined spectroscopically [Poyner, R.R., & Reed, G. H. (1992) Biochemistry 31, 7166-7173]. Remaining ligands for the second Mg2+ are the carbonyl oxygen and gamma-oxygen of Ser 39. Chelation of this Ser residue to Mg2+ effectively "latches" a flexible loop extending from Gly 37 through His 43 and closes off the entrance to the active site. The position of the second Mg2+ in the active site provides new insight into the stereochemistry of substrate binding.
Amino Acid Sequence↗
Proteomic identification of nitrated proteins in Alzheimer's disease brain.
Nitration of tyrosine in biological conditions represents a pathological event that is associated with several neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson's disease and Alzheimer's disease (AD). Increased levels of nitrated proteins have been reported in AD brain and CSF, demonstrating the potential involvement of reactive nitrogen species (RNS) in neurodegeneration associated with this disease. Reaction of NO with O2- leads to formation of peroxynitrite ONOO-, which following protonation, generates cytotoxic species that oxidize and nitrate proteins. Several findings suggest an important role of protein nitration in modulating the activity of key enzymes in neurodegenerative disorders, although extensive studies on specific targets of protein nitration in disease are still missing. The present investigation represents a further step in understanding the relationship between oxidative modification of protein and neuronal death in AD. We previously applied a proteomics approach to determine specific targets of protein oxidation in AD brain, by successfully coupling immunochemical detection of protein carbonyls with two-dimensional polyacrylamide gel electrophoresis and mass spectrometry analysis. In the present study, we extend our investigation of protein oxidative modification in AD brain to targets of protein nitration. The identification of six targets of protein nitration in AD brain provides evidence to the importance of oxidative stress in the progression of this dementing disease and potentially establishes a link between RNS-related protein modification and neurodegeneration.
Aged↗
[Merkel cell carcinoma. Utility of scintigraphy with 111In-DTPA-pentetreotide].
Merkel cell carcinoma (MCC) is an unusual malignant primary skin tumor, having a high incidence of local recurrent, and regional and distant metastasis. Due to its capacity to express somatostatin receptors, it can be detected in vivo with 111In-pentetreotide scintigraphy (Ostreoscan). We present a case of a MCC whose scintigraphy revealed regional metastases of a primary frontal cutaneous tumor that had been removed previously. The results verified a good correlation with clinical, radiological an histopathological findings.
Aged↗
[Biochemical parameters predictive of neuronal damage in childhood].
INTRODUCTION: Hypoxemia, hypoxia and ischemia may induce deletereous effects on both metabolism and cellular structure, particularly at neuronal level. Early estimation of the potential severity of an acute cerebral hypoxic ischemic injury or other pathological conditions would be useful on making preventive or therapeutic decisions. On the basis of the physiopathological mechanisms involved in the brain damage related to hypoxic ischemic encephalopathy of the newborn, a number of metabolic parameters had been studied in the aim to provide an early and reliable marker of tissue injury for both diagnostic and prognostic purposes. OBJECTIVE: To provide a current revision about the diagnostic and prognostic value of various biochemical parameters determined in different body fluids and studied in the last years, the attention focusing in the hypoxic ischemic encephalopathy of the newborn. Design. For methodological purposes the exposition is structured in the following sections: 1. creatine kinase isoenzymes; 2. lactate; 3. lactate dehydrogenase, aspartate aminotransferase and hidroxybutirate dehydrogenase; 4. excitatory amino acids; 5. glial fibrillary acidic protein; 6. cytokines; 7. neuron specific enolase; 8. oxypurines; 9. cyclic adenosine monophosphate; 10. Others. CONCLUSIONS: The current role of the above mentioned biochemical parameters as predictors of brain damage and the future perspectives on this topic are discussed.
Aspartate Aminotransferases↗
Translocation of pp60c-src from the plasma membrane to the cytosol after stimulation by platelet-derived growth factor.
The src family of protein-tyrosine kinases has long been implicated in signal transduction by growth factor receptors. In particular, pp60c-src, the product of the protooncogene c-src, has been shown to associated with the activated platelet-derived growth factor (PDGF) receptor. We demonstrate that, following stimulation of quiescent cells with PDGF, pp60c-src is translocated from the plasma membrane to the cytosol. This phenomenon was better defined utilizing an isolated plasma membrane system. The release of pp60c-src from the membrane in response to PDGF is accompanied by a 4-fold activation of its kinase activity and by phosphorylation at the amino terminus on serine/threonine residues as well as tyrosine residues. This amino-terminal phosphorylation appears to be responsible for a change in hydrophobicity of the pp60c-src molecule and hence for its release from the membrane. The kinase responsible for the serine/threonine phosphorylation and the concomitant release of pp60c-src has been identified as the cAMP-dependent protein kinase. Thus, PDGF stimulation activates at least two membrane-associated kinases (pp60c-src and cAMP-dependent protein kinase) very early in its signal transduction pathway.
3T3 Cells↗
[Solitary capillary hemangioblastoma, cellular variant. Clinical, radiological, and anatomo-pathological study of 2 cases].
Two cases of the rare cellular variant of the solitary capillary haemangioblastoma are reported. On MR study both tumors appeared as cerebellar contrast-enhancing masses, without evidence of intra- or perilesional blood vessels. Histologically, they showed compact groups of polygonal or rectangular cells separated by compressed small capillaries. There were no reticulin fibres among cell clusters. The stromal cells were found to be immunopositive for neuron-specific enolase (NSE), factor VIII-related antigen (von Wille-brand factor), Ulex europaeus lectin, and glial frillary acidic protein (GFAP). The findings are discussed in light of the pertinent literature.
Aged↗