Search results for "Pyruvate Kinase"
showing 10 items of 21 documents
Effect of chronic exercise on glucose uptake and activities of glycolytic enzymes measured regionally in rat heart.
1989
Regional glucose uptake in perfused hearts, and the activities of several glycolytic enzymes contributing to the glucose metabolism in perfused and nonperfused hearts were studied in male and female rats after 8–9 weeks of swimming training. The left ventricular glucose uptake showed a transmural gradient in the sedentary animals, the subendocardial uptake being 30% and 12% higher than that of the subepicardial layer in the males and females, respectively. Swimming exercise abolished the left ventricular glucose uptake gradient in male rats, and in female rats an opposite gradient was found, the subepicardial uptake being 23% higher than the subendocardial uptake. The activities of phosphof…
Detection and Differential Diagnosis of Prekallikrein Deficiency: Genetic Study of New Families and Systematic Review of the Literature
2018
Abstract Introduction. Prekallikrein (PK) and high-molecular-weight kininogen (HK) deficiencies are ultra-rare, autosomal-recessive defects of the contact system caused by biallelic mutations in the KLKB1 and KNG1 genes, respectively. Since affected subjects do not manifest a bleeding phenotype, a correct diagnosis is essential to prevent the administration of prohemostatic agents or plasma and to avoid delay of surgery. We describe a new case of PK deficiency identified at UMC Mainz. In addition, we performed a systematic review of the literature in order to i) collect blood material for genetic studies of reported PK deficient cases lacking this information, and ii) perform a comprehensiv…
Pyruvate kinase type M2: a crossroad in the tumor metabolome.
2002
Cell proliferation is a process that consumes large amounts of energy. A reduction in the nutrient supply can lead to cell death by ATP depletion, if cell proliferation is not limited. A key sensor for this regulation is the glycolytic enzyme pyruvate kinase, which determines whether glucose carbons are channelled to synthetic processes or used for glycolytic energy production. In unicellular organisms pyruvate kinase is regulated by ATP, ADP and AMP, by ribose 5-P, the precursor of the nucleic acid synthesis, and by the glycolytic intermediate fructose 1,6-P2 (FBP), thereby adapting cell proliferation to nutrient supply. The mammalian pyruvate kinase isoenzyme type M2 (M2-PK) displays the …
Protein profiles in human ovarian cancer cell lines correspond to their metabolic activity and to metabolic profiles of respective tumor xenografts
2012
Many solid tumors show a large variability in glycolytic activity and lactate accumulation, which has been correlated with different metastatic spread, radioresistance and patient survival. To investigate potential differences in protein profiles underlying these metabolic variances, the highly glycolytic human ovarian cancer cell line OC316 was investigated and compared with the less glycolytic line IGROV-1. Extracellular acidification and oxygen consumption were analyzed with an extracellular flux analyzer. Glycolysis-associated proteins, including specific membrane transporters, were quantified through in-cell western analyses. Metabolic properties of corresponding tumor xenografts were …
PKM2 promotes Th17 cell differentiation and autoimmune inflammation by fine-tuning STAT3 activation
2019
Th17 cells undergo metabolic reprogramming towards glycolysis to support their differentiation and pathogenicity. Damasceno et al. report that PKM2, a glycolytic enzyme, plays a nonmetabolic role in mediating Th17 cell differentiation and autoimmune neuroinflammation by fine-tuning STAT3 activation.
Influence of inorganic pyrophosphate on the kinetics of muscle pyruvate kinase: a simple nonallosteric feedback model.
2002
Potassium pyrophosphate was used instead of ATP as a model ligand for magnesium cation for the study of effector influence on the kinetics of pyruvate kinase muscle isozyme M1. The pyruvate kinase activation by low concentration of pyrophosphate and inhibition by high concentration of pyrophosphate was considered to be the result of reversible reactions of magnesium cation with pyrophosphate, ADP, ATP, and PEP. The apparent Km and Vm or in some cases the pseudo-first order reaction rate constant (instead of Km and Vm) of pyruvate kinase at any given pyrophosphate concentration were analysed as a function of concentration of free magnesium cation and its complexes with all ligands present in…
A hypothetical model of the influence of inorganic phosphate on the kinetics of pyruvate kinase
2000
This paper presents a simple solution to the problem of approximating the calculated curve of reaction progress to the measured curve which is usually disturbed by initial oscillation of auxiliary lactate dehydrogenase (LDH) reaction. The experiments leading to the determination of the apparent Km for phosphoenolpyruvate (PEP) and Vm were performed. For precise estimation of kinetic parameters (Km and Vm) of the M1 isozyme of pyruvate kinase (PK), measured by coupling it to LDH reaction, the sequence of Michaelis‐Menten for pyruvate kinase and second-order kinetics for lactate dehydrogenase reaction as well as a non-zero initial concentration of lactate was assumed. The functions of apparen…
The quantitative determination of metabolites of 6-mercaptopurine in biological materials. VII. Chemical synthesis by phosphorylation of 6-thioguanos…
1990
Abstract A fast and reliable two-step method has been established for the chemical synthesis of 6-thioguanosine 5′-monophosphate, 6-thioguanosine 5′-diphosphate and 6-thioguanosine 5′-triphosphate starting from the ribonucleoside. In the first step, 6-thioguanosine dissolved in triethyl phosphate, at high yield reacts with phosphorus oxide trichloride to 6-thioguanosine 5′-monophosphate which is purified by anion-exchange chromatography on DEAE-Sephadex using a step gradient of hydrochloric acid. In the second step, 6-thioguanosine 5′-monophosphate dissolved in water, reacts with phosphoric acid in the presence of pyridine/dicyclohexyl carbodiimide and is converted to 6-thioguanosine 5′-dip…
The Charcot Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxida…
2019
Charcot-Marie tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic, and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented…
Metabolic enzymes in coelomic cells (eleocytes) of the polychaete Nereis virens: sex specific changes during sexual maturation
1993
The activities of some enzymes of the intermediary metabolism and the content of soluble protein and carbohydrate (glycogen plus free glucose) were measured in one type of coelomic cells (eleocytes) of the polychaete Nereis virens. Specimens used in this study were collected between 1989 and 1991 in Oosterscheldt Bay, The Netherlands, and divided into six different stages of sexual maturation as determined by the mean oocyte volume. In both sexes, the soluble protein content in eleocytes of immature individuals (11 mg ml−1 cell vol) increased three-fold. In prespawning N. virens the soluble protein content decreased to less than 2 mg protein ml−1 cell vol in females but not in males. In bot…