摘要
After renal injury, selective damage occurs in the proximal tubules as a result of inhibition of glycolysis. The molecular mechanism of damage is not known. Poly(ADP-ribose) polymerase (PARP) activation plays a critical role of proximal tubular cell death in several renal disorders. Here, we studied the role of PARP on glycolytic flux in pig kidney proximal tubule epithelial LLC-PK1 cells using XFp extracellular flux analysis. Poly(ADP-ribosyl)ation by PARP activation was increased approximately 2-fold by incubation of the cells in 10 mM glucose for 30 minutes, but treatment with the PARP inhibitor 3-aminobenzamide (3-AB) does-dependently prevented the glucose-induced PARP activation (approximately 14.4% decrease in 0.1 mM 3-AB-treated group and 36.7% decrease in 1 mM 3-AB-treated group). Treatment with 1 mM 3-AB significantly enhanced the glucose-mediated increase in the extracellular acidification rate (61.1±4.3 mpH/min vs. 126.8±6.2 mpH/min or approximately 2-fold) compared with treatment with vehicle, indicating that PARP inhibition increases only glycolytic activity during glycolytic flux including basal glycolysis, glycolytic activity, and glycolytic capacity in kidney proximal tubule epithelial cells. Glucose increased the activities of glycolytic enzymes including hexokinase, phosphoglucose isomerase, phosphofructokinase-1, glyceraldehyde-3-phosphate dehydrogenase, enolase, and pyruvate kinase in LLC-PK1 cells. Furthermore, PARP inhibition selectively augmented the activities of hexokinase (approximately 1.4-fold over vehicle group), phosphofructokinase-1 (approximately 1.6-fold over vehicle group), and glyceraldehyde-3-phosphate dehydrogenase (approximately 2.2-fold over vehicle group). In conclusion, these data suggest that PARP activation may regulate glycolytic activity via poly(ADP-ribosyl)ation of hexokinase, phosphofructokinase-1, and glyceraldehyde-3-phosphate dehydrogenase in kidney proximal tubule epithelial cells.
Subject(s)
Animals , Cell Death , Epithelial Cells , Glucose , Glucose-6-Phosphate Isomerase , Glycolysis , Hexokinase , Kidney , LLC-PK1 Cells , Oxidoreductases , Phosphofructokinase-1 , Phosphopyruvate Hydratase , Poly Adenosine Diphosphate Ribose , Poly(ADP-ribose) Polymerases , Pyruvate Kinase , Swine摘要
OBJECTIVE@#The aim of this study is to investigate the expression of phosphofructokinase 1 and it's enzyme activity in nasopharyngeal carcinoma biopsy samples.@*METHOD@#Sixty-one biopsy samples were detected, including 41 tissues from patients with nasopharyngeal carcinoma as experimental group and 20 tissues from patients with chronic nasopharyngitis as control group. Phosphofructokinase 1 protein was detected by Western blot and it's enzyme activity was detected.@*RESULT@#It was observed that the expression levels of phosphofructokinase 1 protein and it's enzyme activities in the experimental group were higher than that in the control group (P < 0.01). In the experimental group, the expression levels of phosphofructokinase 1 protein and it's enzyme activities in patients with lymph node metastasis were higher than that in patients without lymph node metastasis (P < 0.01).@*CONCLUSION@#Phosphofructokinase 1 may be a marker in occurrence and metastasis of nasopharyngeal carcinoma.
Subject(s)
Humans , Biomarkers, Tumor , Metabolism , Biopsy , Carcinoma , Case-Control Studies , Lymphatic Metastasis , Nasopharyngeal Carcinoma , Nasopharyngeal Neoplasms , Pathology , Nasopharyngitis , Phosphofructokinase-1 , Metabolism摘要
OBJECTIVE@#The aim of this study is to investigate the expression and clinical significance of 6-phosphofructo-1-kinase in nasopharyngeal carcinoma biopsy samples.@*METHOD@#Sixty-one biopsy samples were detected, including 41 tissues samples from patients with nasopharyngeal carcinoma and 20 tissues samples from patients with chronic nasopharyngitis as control group. 6-phosphofructo 1 kinase mRNA expression was detected by RTPCR.@*RESULT@#It was observed that the expression levels of 6 phosphofructo-1-kinase mRNA in nasopharyngeal carcinoma tissues were higher than in the chronic inflammatory tissues. And the expression levels in patients with lymph node metastasis were higher than without lymph nod metastasis.@*CONCLUSION@#6-phosphofructo-1-kinase may be a marker in occurrence and metastasis of nasopharyngeal carcinoma.
Subject(s)
Female , Humans , Male , Biomarkers, Tumor , Metabolism , Carcinoma , Lymphatic Metastasis , Nasopharyngeal Carcinoma , Nasopharyngeal Neoplasms , Metabolism , Pathology , Phosphofructokinase-1 , Genetics , Metabolism , RNA, Messenger , Metabolism摘要
O vírus Influenza é o agente infeccioso que mais afeta o trato respiratório dos seres humanos, resultando em altos índices de morbidade e mortalidade. Este vírus pertence à família Orthomyxovirida, apresenta RNA fita simples, octa-segmentado, de polaridade negativa e possui um envelope lipoproteico no qual estão inseridas as glicoproteínas hemaglutinina e neuraminidase. Já foi demonstrado que a infecção por Influenza gera alterações no metabolismo celular, porém, não foi descrito, até o momento, qual seria o mecanismo de ação relacionado. Em nosso trabalho, decidimos analisar mais a fundo essas alterações metabólicas relacionadas à infecção por Influenza A. Para tal, resolvemos investigar os efeitos da inibição da via glicolítica e do silenciamento da enzima chave de regulação da via, a enzima PFK -1, sobre a replicação viral. Inicialmente, utilizamos células MDCK infectadas com MOI de 5,0 e verificamos o efeito da inibição de umas das etapas finais desta via metabólica sobre a replicação do vírus. Observamos que, em 24 horas pós-infecção, a inibição da glicólise provocou uma redução da replicação do vírus Influenza, porém, em 48 horas pósinfecção, a inibição desta via promoveu um aumento da replicação viral. Verificamos, também, que o silenciamento das isoformas L, M e P da enzima PFK-1, em 24 horas pós-infecção, promoveu uma significativa diminuição do título viral. Diante disto, decidimos investigar quais as etapas do ciclo replicativo estariam sendo afetadas pelo silenciamento desta enzima e observamos que, tanto a adsorção como a penetração de material genético no núcleo celular foram afetadas pelo silenciamento da PFK-1, principalmente pela inibição da isoforma P. Esses resultados sugerem que a enzima PFK-1 tem um importante papel na infecção pelo vírus Influenza podendo, inclusive, ser um possível alvo terapêutico.
Subject(s)
Influenza A virus , Phosphofructokinase-1摘要
This research aimed to study the effect of distillage recycling on ethanol fermentation, the key glycolytic enzymes and cell composition of the self-flocculating yeast. With the self-flocculating yeast SPSC01 and medium composed of 220 g/L glucose, 8 g/L yeast extract and 6 g/L peptone, continuous ethanol fermentation was carried out at the dilution rate of 0.04 h(-1) with a 1.5 L tank bioreactor. Fermentation broth was collected every 3 days, and ethanol and other volatile byproducts were removed by distillation, but the stillage with high boiling byproducts was recycled to prepare the medium instead of fresh water. The system was run for 20 days, during which ethanol and biomass concentrations in the effluent decreased continuously, indicating the significant inhibition of the high boiling byproducts accumulated within the system. Thus, the activities of the key enzymes of the glycolytic pathway: hexokinase, 6-phosphofructose kinase, and pyruvate kinase were analyzed, and it was observed that all of them were inhibited. Furthermore, the biosynthesis of the stress response metabolites glycerol and trehalose was investigated, and it was found that glycerol production that can protect yeast cells against osmotic pressure stress was enhanced, but trehalose biosynthesis that can protect yeast cells against ethanol inhibition was not improved, correspondingly. And in the meantime, the biosynthesis of the major intracellular components proteins and hydrocarbons was adjusted, correspondingly.
Subject(s)
Bioreactors , Microbiology , Ethanol , Metabolism , Fermentation , Flocculation , Glycerol , Metabolism , Glycolysis , Hexokinase , Metabolism , Industrial Microbiology , Methods , Phosphofructokinase-1 , Metabolism , Saccharomyces cerevisiae , Genetics , Metabolism , Schizosaccharomyces , Genetics , Metabolism , Trehalose , Metabolism , Triticum , Metabolism , Zea mays , Metabolism摘要
<p><b>OBJECTIVE</b>To investigate the influence of microtubule intervention drugs on glycolytic key enzymes in myocardial cells after hypoxia.</p><p><b>METHODS</b>The primary passage of cultured myocardial cells from neonatal rats were divided into A group (with hypoxia), B group (with hypoxia and administration of l0 micromol/L colchicine), C group (with hypoxia and administration of 5 micromol/L taxol), D group (with hypoxia and administration of 10 micromol/L taxol), E group (with hypoxia and administration of 15 micromol/L taxol). The morphology of microtubule was observed with laser scanning microscope (LSM). The cell vitality was assayed by cell counting kit (CCK). The activities of hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) were assayed with colorimetry.</p><p><b>RESULTS</b>In group B and E, the microtubule structure was damaged heavily, and the cell vitality was decreased significantly [The cell vitality was (89.99 +/- 3.47)% in B group and (84.56 +/- 6.61)% in E group, respectively, at 1.0 post hypoxia hour (PHH), and hoth values were obviously lower than that in A group (97.44 +/- 1.76)%, P < 0.01]. The HK, PK and PFK activities decreased obviously. The activities of HK, PK and PFK in group C were similar to those of the A group. Compared with that in other groups, the degree of damage of microtubule structure in D group was milden. The activities of HK, PK and PFK in D group during 0.5 - 6.0 PHH were significantly higher than those in A group. The activity of LDH in each group was increased after hypoxia.</p><p><b>CONCLUSION</b>Proper concentration of microtubule-stabilizing drugs can alleviate the damages to microtubule structure, and enhance the activity of glycolytic key enzymes of myocardial cells at early stage of hypoxia.</p>
Subject(s)
Animals , Rats , Cell Hypoxia , Cells, Cultured , Glycolysis , Hexokinase , Metabolism , L-Lactate Dehydrogenase , Metabolism , Microtubules , Metabolism , Myocytes, Cardiac , Metabolism , Phosphofructokinase-1 , Metabolism , Pyruvate Kinase , Metabolism , Rats, Sprague-Dawley摘要
6-phosphofructo-1-kinase (phosphofructokinase; PFK) activity from Rhodnius prolixus, a haematophagous insect which is usually a poor flyer, was measured and compared in two metabolically active tissues - flight muscle and fat body. The activity of this important regulatory glycolytic enzyme was much more pronounced in muscle (15.1 ± 1.4 U/mg) than in fat body extracts (3.6±0.4 U/mg), although the latter presented higher levels of enzyme per protein content, as measured by western-blotting. Muscle extracts are more responsible than fat body to ATP and fructose 6-phosphate, both substrates of PFK. Allosteric regulation exerted by different effectors such as ADP, AMP and fructose 2,6-phosphate presented a singular pattern for each tissue. Optimal pH (8.0-8.5) and sensitivity to pH variation was very similar, and citrate was unable to inhibit PFK activity in both extracts. Our results suggest the existence of a particular PFK activity for each tissue, with regulatory patterns that are consistent with their physiological roles.
A atividade da fosfofrutocinase (PFK) de Rodnius prolixus, um inseto hematófago, o qual vôa somente pequenas distâncias, foi medida e comparada em dois tecidos metabolicamente ativos - músculo de asa e corpo gorduroso. A atividade desta importante enzima glicolítica regulatória foi muito mais pronunciada em músculo de asa (15,1 ±1,4 U/mg) do que em extrato de corpo gorduroso (3,6 ±0,4 U/mg) embora este último tenha apresentado níveis mais altos da enzima por quantidade de proteína, como medido por western-blotting. Extratos de músculo foram mais responsivos do que corpo gorduroso para ATP e frutose-6-fosfato, ambos substratos da PFK. A regulação alostérica exercida por diferentes efetores tais como ADP, AMP, frutose-2,6-bisfosfato apresentou um padrão singular para cada tecido. O pH ótimo (8,0-8,5) e a sensibilidade a variações de pH, foram muito similares e o citrato foi incapaz de inibir a atividade da PFK em ambos os extratos. Nossos resultados sugerem a existência de uma atividade particular da PFK para cada tecido com padrões regulatórios que são consistentes com suas funções fisiológicas.
Subject(s)
Animals , Fat Body/enzymology , Muscle, Skeletal/enzymology , Phosphofructokinase-1/metabolism , Phosphofructokinase-1/physiology , Rhodnius/enzymology , Allosteric Regulation/physiology , Blotting, Western , Kinetics摘要
Apesar de existirem muitos estudos sobre a influência do diabetes nas glândulas salivares, esses apresentam resultados conflitantes. Neste estudo, a regulação da enzima fosfofrutoquinase-1 (PFK-1) foi estudada utilizando-se glândulas salivares de ratos. O diabetes foi induzido por uma única injeção intraperitonial de estreptozotocina (60 mg/kg peso corporal) em ratos (180-200 g). Os animais foram sacrificados 30 dias após a indução do diabetes e utilizaram-se as glândulas submandibular e parótida. A hiperglicemia foi avaliada por determinação da glicemia sanguínea. A distribuição da PFK-1 entre frações solúvel e ligada, concentração de fosfato na PFK-1, concentração de frutose-2,6-bisfosfato e a atividade da enzima PFK-2 foram determinadas. O cálculo do peso glandular relativo mostrou um aumento na glândula parótida de ratos diabéticos comparados ao controle, o que não ocorreu na glândula submandibular. A atividade da PFK-1 expressa por glândula não mostrou variação entre animais diabético e controle. Contudo, considerando a atividade específica, a fração solúvel da enzima mostrou aumento de 50% com relação ao controle e a fração ligada ao citoesqueleto um aumento de 84% com relação ao controle. Na glândula parótida não foi observada diferença na atividade específica entre os grupos diabético e controle. Por outro lado, a atividade por glândula da fração solúvel aumentou nos animais diabéticos. A concentração de fosfato da PFK-1 aumentou nas glândulas submandibular e parótida nos animais diabéticos. Tanto a concentração de frutose-2,6-bisfosfato quanto a forma ativa da PFK-2 mostraram redução nas glândulas salivares. Concluindo, o aumento na atividade da PFK-1 observado nas glândulas salivares de ratos com diabetes induzida por estreptozotocina não parece ser modulado pela frutose-2,6-bisfosfato.
Subject(s)
Animals , Male , Rats , Diabetes Mellitus, Experimental/enzymology , Phosphofructokinase-1/metabolism , Salivary Glands/enzymology , Cytoskeleton/enzymology , Diabetes Mellitus, Experimental/chemically induced , Parotid Gland/enzymology , Phosphofructokinase-1/analysis , Rats, Wistar , Streptozocin , Submandibular Gland/enzymology摘要
<p><b>OBJECTIVE</b>To investigate the influence of hypoxia induction factor-1alpha (HIF-1alpha) on glycosis of rat myocardial cell under hypoxic condition.</p><p><b>METHODS</b>The myocardial cells of the rats were routinely isolated and cultured. The cells were divided into single hypoxia (H) and HIF-1alpha inhibiting (I) groups. The cells in H group were cultured in glucose-free medium with mixed low-oxygen gas [1% O2, 94% N2 and 5% CO2 (v/v)]. While the cells in I group were cultured with low-oxygen gas after the cell model of low expression of HIF-1alpha protein constructed by RNAi technique. The cells in both groups were all observed before hypoxia (routine culture) and at the time points of 1, 3, 6, 12 and 24 hours of hypoxia. The LA (lactate acid ) content in the supernatant of the culture and the activity of the key enzymes in glycolysis such as hexokinase (HK), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) of both groups of cells were determined at all the time points.</p><p><b>RESULTS</b>(1) After hypoxia, the HK and PFK activities of the rat myocardial cells in H and I groups were obviously increased at the beginning and decreased thereafter when compared with that before hypoxia. While the activities of HK and PFK in H group at 1, 3 and 6 hours after hypoxia were evidently higher than those in I group (P <0.05 or 0.01), and the peak activity of them in H and I groups was 159 +/- 13 U/g vs 133 +/- 55 U/g, and 298 +/- 44 U/g vs 188 +/- 55 U/g, respectively. (2) Compared with normal control (92 +/- 12 U/g), the LDH activity of the cells in H group after hypoxia increased significantly, reaching the peak at 6 hours after hypoxia (2 568 +/- 125 U/g, P < 0. 01), and it decreased thereafter, while that in I group peaked at 3 hours after hypoxia (2125 +/- 126 U/g, P <0.01). The LA content in the culture supernatant in H group increased significantly after hypoxia with the passage of time, while that in I group increased in smaller magnitude (P <0.01).</p><p><b>CONCLUSION</b>High expression of HIF-1alpha in the rat myocardial cells after hypoxia could directly cause continuous enhancement of cell glycolysis, which was beneficial to the protection of myocardial cells under hypoxic condition.</p>
Subject(s)
Animals , Rats , Cell Hypoxia , Cells, Cultured , Glycolysis , Hexokinase , Metabolism , Hypoxia-Inducible Factor 1, alpha Subunit , Metabolism , L-Lactate Dehydrogenase , Metabolism , Myocytes, Cardiac , Metabolism , Phosphofructokinase-1 , Metabolism , RNA Interference , Rats, Sprague-Dawley摘要
The effect of Capparis spinosa [C. spinosa] and Acacia arabica [A. arabica] dry powder as plant molluscicide on some glycolytic and gluconeogenic enzymes on snail tissues was investigated. Lactate dehydrogenase [LDH], pyruvate kinase [PK], hexokinase [HK], phosphofructokinase [PFK], glucose phosphate isomerase [GPI] as important glycolytic enzymes were markedly manipulated by both plants when measured one day and one week post-treatment. On the other hand, glucose-6-phosphatase [G-6-Pase], fructose 1.6 diphosphatase [FDpase], phosphoenolpyruvate carboxykinase [PEPCK] as gluconeogenic enzymes were significantly affected by the molluscicidal plants. In addition, some other parameters as glycogen, glucose, total protein, 5-nucleotidase alpha-hydroxybutyrate dehydrogenase [HBDH] and succinate dehydrogenase [SDH] as Krebs cycle enzyme were tested. The study concluded that LC25 and LC50 concentrations of C. spinosa and A. arabica might render B. alexandrina physiologically unsuitable for S. mansoni infection
Subject(s)
Snails , Lactate Dehydrogenases , Pyruvate Kinase , Hexokinase , Phosphofructokinase-1 , Plant Structures , Gum Arabic , Biomphalaria摘要
The changes in activities of certain enzymes in the liver of ethanol ingested rats and the corrective action of carnosine treatment was studied in the present work. These enzymes included, alcohol dehydrogenase [adh] and some enzymes of energy metabolism including, hexokinase hk. Phosphofructokinase [pfk], malate dehydrogenase [mdh] and creatine phosphokinase [cpk]. Ethanol ingestion showed a marked reduction in the activities of energy metabolism enzymes, indicating the toxic effect of ethanol by inducing oxidative stress on liver tissues, administration of carnosine ameliorated the toxic action of ethanol by improving the activities of the four energy metabolism enzymes
Subject(s)
Animals, Laboratory , Carnosine/pharmacology , Hexokinase , Alcohol Dehydrogenase , Phosphofructokinase-1 , Creatine Kinase , Ethanol , Oxidative Stress , Rats , Liver/drug effects摘要
The effects of short-term burst (5 min at 1.8 m/s) swimming and long-term cruiser (60 min at 1.2 m/s) swimming on maximal enzyme activities and enzyme distribution between free and bound states were assessed for nine glycolytic and associated enzymes in tissues of horse mackerel, Trachurus mediterraneus ponticus. The effects of exercise were greatest in white muscle. The activities of phosphofructokinase (PFK), pyruvate kinase (PK), fructose-1,6-bisphosphatase (FBPase), and phosphoglucomutase (PGM) all decreased to 47, 37, 37 and 67 percent, respectively, during 60-min exercise and all enzymes except phosphoglucoisomerase (PGI) and PGM showed a change in the extent of binding to subcellular particulate fractions during exercise. In red muscle, exercise affected the activities of PGI, FBPase, PFK, and lactate dehydrogenase (LDH) and altered percent binding of only PK and LDH. In liver, exercise increased the PK activity 2.3-fold and reduced PGI 1.7-fold only after 5 min of exercise but altered the percent binding of seven enzymes. Fewer effects were seen in brain, with changes in the activities of aldolase and PGM and in percent binding of hexokinase, PFK and PK. Changes in enzyme activities and in binding interactions with subcellular particulate matter appear to support the altered demands of tissue energy metabolism during exercise
Subject(s)
Animals , Enzymes/metabolism , Fishes/physiology , Glycolysis/physiology , Muscle, Skeletal/enzymology , Physical Exertion/physiology , Brain/enzymology , Enzymes/analysis , Fructose-Bisphosphatase/metabolism , Liver/enzymology , Phosphofructokinase-1/metabolism , Phosphoglucomutase/metabolism , Swimming摘要
The activity of important glycolytic enzymes (hexokinase, phosphofructokinase, aldolase, phosphohexoseisomerase, pyruvate kinase and lactate dehydrogenase) and glutaminolytic enzymes (phosphate-dependent glutaminase) was determined in the thymus and mesenteric lymph nodes of wistar rats submited to protein malnutrition (6 percent protein in the diet rather than 20 percent) from conception to 12 weeks after birth. The wet weight (g) of the thymus and mesenteric lymph nodes decreased due to protein malnutrition by 87 percent (from 0.30 + 0.05 to 0.04 + 0.01) and 75 percent (0.40 + 0.04 to 0.10 + 0.02), respectively. The protein content was reduced only in the thymus from 102.3 + 4.4 (control rats) to 72.6 + 6.6 (malnourished rats). The glycolytic enzymes were not affected by protein malnutrition, but the glutaminase activity of the thymus and lymph nodes was reduced by halfing in protein-malnourished rats as compared to controls. This fact may lead to a decrease in the cellularity of the organ and thus in its size, weight and protein content.
Subject(s)
Rats , Male , Animals , Dietary Proteins/metabolism , Fructose-Bisphosphate Aldolase/metabolism , Glucose-6-Phosphate Isomerase/metabolism , Glucose/metabolism , Glutaminase/metabolism , Glutamine/metabolism , Glycolysis/physiology , Hexokinase/metabolism , L-Lactate Dehydrogenase/metabolism , Lymph Nodes/enzymology , Phosphofructokinase-1/metabolism , /metabolism , Protein-Energy Malnutrition/enzymology , Pyruvate Kinase/metabolism , Thymus Gland/enzymology , Rats, Wistar摘要
La sialadenosis en animales de laboratorio puede ser provocada por la administración de un agonista betadrenérgico conocido como isoproterenol. Su efecto produce hipertrofia e hiperplasia de las glándulas salivales, especialmente de la glándula parótida. La 6-fosfofructo-2-quinasa (PKF-2) es una enzima bifuncional que cataliza tanto la síntesis como la degradación de la fructosa-2,6-difosfato. este metabolito es un potente activador de la 6-fosfofructo-1-quinasa (PKF-1) enzima clave en el proceso glucolítico. En este trabajo determinamos la actividad de la PKF-2 y el contenido de fructosa-2,6-bifosfato en glándulas parótidas de ratas, al ser estimuladas con varias dosis de isoproterenol
Subject(s)
Animals , Rats , Fructose-1,6-Diphosphatase Deficiency/chemically induced , Parotid Gland , Isoproterenol/pharmacokinetics , Phosphofructokinase-1/drug effects , Rats, Sprague-Dawley/metabolism摘要
Chemical modification is usually employed to study enzyme active sites. Valuable information can also be obtained, however, when this technique is used to probe allosteric sites. This approach is discussed in this article, and it is exemplified in chemical modification studies of the allosteric enzyme phosphofructokinase
Subject(s)
Allosteric Regulation/physiology , Allosteric Site/physiology , Enzyme Activation/physiology , Ligands , Mutagenesis, Site-Directed/physiology , Phosphofructokinase-1/chemistry , Protein Conformation , Sulfhydryl Compounds/chemistry , Adenosine Triphosphate/chemistry , Citrates/chemistry , Fructose/chemistry摘要
Specimens of Trematomus bernacchii were caught by hooks near the Japanese Antarctic Station of Syowa during the month of January, 1992. The caught animals were taken to the Laboratory at the Icebreaker Shirase. Epaxial and cardiac muscles were dissected, washed thoroughly with chilled saline and used for the preparation of phosphofructokinase (PFK) and hexokinase (HK). Liver, encephalon, and whole blood were also obtained and used for the preparation of crude extracts and hemolysates. The following kinetic data were obtained for PFK: the apparent Km for F-6-P in the presence of 216MuM of ATP; the apparent Km for ATP in the presence 1mM of F-6-P. In both cases, the experiments were carried out at 20 degrees Celsius, pH 8.0. At this pH, the fish PFK did not display allosteric properties. The allosteric behavior of this preparation of PFK was assayed at pH 7.0. Levels of HK assayed in tissues crude extracts and red blood cells hemolysates gave the following results in specific activity (mU/mg protein): cardiac muscle, 62; encephalon, 18; liver, 2.7; RBC hemolysates, 0.0; epaxial muscle, 0.0. The ATP and glucose apparent Km were assayed for the cardiac muscle HK.
Subject(s)
Animals , Fishes/metabolism , Hexokinase/pharmacokinetics , Phosphofructokinase-1/pharmacokinetics , Antarctic Regions摘要
El objetivo de la presente revisión es describir los efectos que tienen algunos moduladores descritos recientemente en la literatura, sobre la actividad de la 6-fosfofructo-1-quinasa. Esta enzima es clave del proceso glicolitico y su control se realiza mediante fosforilación/defosforilación, en los distintos tejidos estudiados
Subject(s)
Carbohydrates/metabolism , Glycolysis/physiology , In Vitro Techniques , Phosphofructokinase-1/physiology , Isoenzymes/physiology摘要
The hypoglycemic effect of Bordetella pertussis (Challenge strain No.18323) purified cell extract (protein with traces of carbohydrates, 2 mg%) administered (0.1 mg/100 g body wt. i.v.) into mice on the activities of the key regulatory enzymes, viz. glucokinase, phosphofructokinase, pyruvate kinase, glyceraldehyde phosphodehydrogenase, glucose-6-phosphate dehydrogenase (G-6-PD) and lactate dehydrogenase, of glycolytic pathway in liver has been studied at varying intervals after injection. The maximum hypoglycaemic effect was observed at the end of 12 hr, while activities of all the enzymes studied showed significant enhancement after 18 hr, thus suggesting increased glucose utilization towards the formation of pyruvate. Actinomycin D is found to inhibit stimulation of G-6-PD activity in B. pertussis treated animals, thereby indicating the role of B. pertussis in synthesis of this enzyme.
Subject(s)
Animals , Bordetella pertussis , Glucokinase/metabolism , Glucosephosphate Dehydrogenase/metabolism , Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism , Glycolysis/drug effects , L-Lactate Dehydrogenase/metabolism , Liver/drug effects , Male , Mice , Pertussis Vaccine/pharmacology , Phosphofructokinase-1/metabolism , Pyruvate Kinase/metabolism , Time Factors摘要
Effects of prolactin (PRL), bromocriptine (Br), testosterone propionate (TP), dihydrotestosterone (DHT) and the combinations of these androgens with PRL/Br on the specific activities of caudal and cranial prostatic cellular enzymes involved in carbohydrate metabolism in castrated mature bonnet monkeys have been studied. Castration decreased all the enzymes studied such as hexokinase (HK), 6-phosphofructokinase (6-PFK), glyceraldehyde-3-phosphate dehydrogenase (G-3-PD), pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G-6-PD) and 6-phosphogluconate dehydrogenase (6-PGD) in the cranial and caudal prostates. PRL elevated the activities of all the enzymes above normal except G-3-PD of cranial lobe. In the caudal lobe, PRL brought back the activities of HK, PFK, PK, G-6-PD to normal and 6-PGD above normal except G-3-PD. TP/DHT treatment increased all the enzymes in both the lobes. PRL given along with TP/DHT further enhanced the androgen action with regard to HK, PK, G-6-PD and 6-PGD of cranial and PFK, G-3-PD, PK, G-6-PD and 6-PGD of caudal lobe. Br treatment did not produce any alteration of these enzymes in both the lobes. In the cranial lobe, during Br+TP/DHT treatment, the stimulating effects of androgen were unaffected on all the enzymes except PK. On the other hand in the caudal, the stimulatory effects of androgens were affected and the activities of HK, PFK, PK and 6-PGD were significantly decreased. The present results suggest that PRL has a direct as well as a synergistic action with androgens on enzymes of EMP and HMP shunt in the prostates of monkeys.