DOCSLIB.ORG

Bioenergetics and High-Energy Compounds

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Bioenergetics and High-Energy Compounds Bioenergetics and high-energy compounds Tomáš Kučera [email protected] Department of Medical Chemistry and Clinical Biochemistry 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital 2017 Bioenergetics how organisms gain, convert, store and utilize energy Gibbs free energy G = H − TS ) ∆G = ∆H − T∆S = Qp − T∆S G decrease in a biological process represents its maximum recoverable work. equilibrium: ∆G = 0 spontaneous (exergonic) process: ∆G < 0 (it can do work) endergonic process: ∆G > 0 Gibbs free energy one of the thermodynamic potentials no information on the rate – it is given by the mechanism (im-)possibility of a process given only by the initial and final states a catalyst (enzyme) can accelerate equilibrium aainment, not change its state ) possibility of coupling = ∆H depends on temperature: equilibrium: T ∆S ∆H ∆S ∆G = ∆H − T∆S − + Both enthalpically favored (exothermic) and entropically favored. Spontaneous (exergonic) at all temperatures. − − Enthalpically favored but entropically opposed. Sponta- = ∆H neous only at temperatures below T ∆S . + + Enthalpically opposed (endothermic) but entropically fa- = ∆H vored. Spontaneous only at temperatures above T ∆S . + − Both enthalpically and entropically opposed. Unspontaneous (endergonic) at all temperatures. Rewrien from Voet, D., Voet, J. G.: Biochemistry, John Wiley & Sons, Inc., 2011 (4th edition) Chemical equilibria Reaction a A + b B c C + d D [C]c[D]d ∆G =∆ G0 + RT ln [A]a[B]b (∆G0 = standard G change of the reaction) constant term — depends only on the reaction variable term — depends on temperature and concentrations of reactants and products Equilibrium ∆G = 0 c d [C] [D] −∆G0 + K = = e RT eq [ ]a[ ]b 0 A B ∆G = −RT ln Keq 0 ∆G and Keq directly related 0 −1 10-fold change in Keq changes ∆G by 5.7 kJ mol Free energy changes 0 X 0 X 0 ∆G = ∆Gf (products) − ∆Gf (reactants) 0 0 ∆Gf = ∆G of formation 0 −1 0 −1 Compound ∆Gf (kJ mol ) Compound ∆Gf (kJ mol ) acetaldehyde 139.7 glyceraldehyde-3-phosphate2– 1285.6 acetate 369.2 H+ 0.0 a acetyl-CoA 374.1 H2 (g) 0.0 3– cis-aconitate 920.9 H2O (l) 237.2 3– CO2 (g) 394.4 isocitrate 1160.0 2– CO2 (aq) 386.2 a-ketoglutarate 798.0 – – HCO3 587.1 lactate 516.6 3– citrate 1166.6 l-malate2– 845.1 dihydroxyacetone2– 1293.2 OH– 157.3 ethanol 181.5 oxaloacetate2– 797.2 fructose 915.4 phosphoenolpyruvate3– 1269.5 2– fructose-6-phosphate 1758.3 2-phosphoglycerate3– 1285.6 4– fructose-1,6-bisphosphate 2600.8 3-phosphoglycerate3– 1515.7 2– fumarate 604.2 pyruvate– 474.5 a-d-glucose 917.2 succinate2– 690.2 2– glucose-6-phosphate 1760.3 succinyl-CoA 686.7a a for formation from free elements + free CoA Rewrien aer Voet, D., Voet, J. G.: Biochemistry, John Wiley & Sons, Inc., 2011 (4th edition) Free energy changes standard state activity 1 mol l−1 25 ◦C 1 bar biochemical standard state water activity = 1 pH = 7 substances undergoing acid-base dissociation: c = total c of all species at pH = 7 Coupled reactions A + B C + D ∆G1 D + E F + G ∆G2 A + B + E C + F + G ∆G3 = ∆G1 + ∆G2 < 0 Glucose phosphorylation: Glc + ATP Glc-6- P + ADP endergonic reaction: glucose + P glucose-6- P ∆G00 = 13:8 kJ mol−1 exergonic reaction: 00 −1 ATP + H2O ADP + P ∆G = −30:5 kJ mol coupled reaction: Glc + ATP Glc-6- P + ADP ∆G00 = −16:7 kJ mol−1 Redox potential also oxidation-reduction (reduction) potential expresses the substance’s readiness to accept electrons n – ox + e red (half-cell) Voet, D., Voet, J. G.: Biochemistry, John Wiley & Sons, Inc., 2011 (4th edition) n e– Aox + Bred Ared + Box Nernst equation [A ][B ] ∆G = ∆G0 + RT ln red ox [Aox][Bred] ∆G = −nF ∆E RT [red] RT [A ][B ] E = E0 − ·ln ) ∆E = ∆E0 − ·ln red ox nF [ox] nF [Aox][Bred] Redox potential E as an energy scale Reduced form Oxidized form E0´(V) ΔG0´ acetaldehyde acetate -0,60 – values higher + H2 2H -0,42 (reductant) isocitrate 2-oxoglutarate + CO2 -0,38 glutathione-SH glutathione-SS -0,34 + + n NADH + H NAD -0,32 n o o i i t t c glyceraldehyde-3-phosphate + H3PO4 1,3-bisphosphoglycerate -0,28 c a a e e r r FADH2 FAD -0,20 c c i i n n lactate pyruvate -0,19 o – – o g +ne –ne g r r e malate oxalacetate -0,17 e d x n e cytochrome b (Fe2+) cytochrome b (Fe3+) 0,00 e succinate fumarate +0,03 dihydroubiquinone ubiquinone +0,10 cytochrome c (Fe2+) cytochrome c (Fe3+) +0,26 H2O2 O2 +0,29 + values H2O ½ O2 +0,82 (oxidant) lower Voet, D., Voet, J. G.: Biochemistry, John Wiley & Sons, Inc., 2011 (4th edition) The actual direction of the reaction depends also on the [red]/[ox] ratio (and/or other factors) Redox potential E0 = 0 V for standard hydrogen half-reaction (electrode) H+ at pH0, 25 ◦C, 1 bar in equilibrium with Pt-black electrode saturated with H2 pH = 7 ) E00 = −0:421 V High-energy compounds contain “high-energy bond” hydrolyzed to drive endergonic reactions ATP a central role (universal “energy currency” of the cell) 3 phosphoryl groups bound by one phosphoester and two phosphoanhydride bonds NH2 phosphoanhydride phosphoester N bonds bond N O O O – O Pγ O Pβ O Pα O O N N O– O– O– H H H H OH OH adenosine AMP ADP ATP Redrawn according to Voet, D., Voet, J. G.: Biochemistry, John Wiley & Sons, Inc., 2011 (4th edition) ATP R1 O P + R2 OH R1 OH + R2 O P phosphoryl transfer reaction – enormous metabolic significance 0 −1 ATP + H2O ADP + P ∆G = −30:5 kJ mol 0 −1 ATP + H2O AMP + P P ∆G = −45:6 kJ mol 0 −1 P P + H2O 2 P ∆G = −19:2 kJ mol kinetic stability, thermodynamic instability (high |−∆G0j) cell energy charge (usually 0.8–0.95) [ ] + 1 [ ] ATP 2 ADP [ATP] + [ADP] + [AMP] adenylate kinase: ATP + AMP 2 ADP ATP is formed using more exergonic reactions Coupled reactions A B ∆G00 = 16:7 kJ mol−1 0 [B] −∆G −3 = Keq = e RT = 1:15 · 10 [A] + A + ATP + H2O B + ADP + P + H ∆G00 = −13:8 kJ mol−1 [B] [ADP][ P ] 2 Keq = · = 2:67 · 10 [A] [ATP] at equilibrium: [B] [ATP] 2 5 = Keq = 2:67 · 10 · 500 = 1:34 · 10 [A] [ADP][ P ] the equilibrium B/A ratio is 108times higher! n ATP molecules hydrolyzed ) the ratio is 108ntimes higher! ATP consumption “low-energy” phosphorylated compounds NTP interconversions formation of CTP, GTP, UTP, dATP, dCTP, dGTP, dTTP nucleoside diphosphate kinase ATP + NDP ADP + NTP processes based on protein conformational changes protein folding active transport movements ATP ATP formation substrate-level phosphorylation oxidative phosphorylation (photophosphorylation) adenylate kinase reaction phosphagens ATP turnover average adult resting person about 3 mol h−1 (1.5 kg h−1), i.e. about 40 kg d−1 strenuous activity – up to 0.5 kg min−1 “High-energy bonds” phosphoanhydrides resonance stabilization higher solvation energy of the hydrolysis products electrostatic repulsion – – – O O O O O– O– + P – P – P + P – P + P HO O HO O HO O HO O RO – – – – O O O O O O O– O– Redrawn from Berg, J. M.,Gao, G. Tymoczko, J. Jr., J.Biochemistry, L., W. H. Stryer, Freeman L.: and Company, 2012 (8th edition) other anhydrides phosphosulphates, acylphosphates carbamoylphosphate phosphoguanidines (phosphagens) – phosphocreatine, phosphoarginine enol phosphates thioesters there are no high-energy compounds as well! High-energy compounds NH2 N N O O O CH3 O O O O H – – H2C C O P O O P N C N CH2 C –O P O P O P O N O N – – + – O O NH2 O O– O– O– H H H H acetylphosphate (acylphosphates)phosphocreatine (phosphamides) OH OH adenosine triphosphate (ATP) O −O P O− NH2 O O N N O O H2C C C CoA S COCH3 – – O O P O P O O N N O– O– H H phosphoenolpyruvate (enolphosphates)acetylcoenzyme A (thioesters) H H OH OH adenosine diphosphate (ADP) Energy metabolism scheme alternative amino acids fatty acids sugars pathways lactate NADH NAD+ ethanol propionate butyrate butanol fermentative formate NADH + glycolysis NAD H + 2 β-oxidation NAD regeneration CO2 acetate 2,3-butandiol pyruvate succinate oxidative decarboxylation citric acid Calvin cycle cycle Ac~S–CoA CO2 NADH NAD+ NADPH NADP+ hν photosynthetic ADP respiratory chain O electron transport ADP 2 chain oxidative phosphorylation H O photophosphorylation ATP 2 ATP The End konec – the end Thank you for your aention! one of the thermodynamic potentials no information on the rate – it is given by the mechanism (im-)possibility of a process given only by the initial and final states a catalyst (enzyme) can accelerate equilibrium aainment, not change its state ) possibility of coupling Gibbs free energy = ∆H depends on temperature: equilibrium: T ∆S ∆H ∆S ∆G = ∆H − T∆S − + Both enthalpically favored (exothermic) and entropically favored. Spontaneous (exergonic) at all temperatures. − − Enthalpically favored but entropically opposed. Sponta- = ∆H neous only at temperatures below T ∆S . + + Enthalpically opposed (endothermic) but entropically fa- = ∆H vored. Spontaneous only at temperatures above T ∆S . + − Both enthalpically and entropically opposed. Unspontaneous (endergonic) at all temperatures. Rewrien from Voet, D., Voet, J. G.: Biochemistry, John Wiley & Sons, Inc., 2011 (4th edition) 0 X 0 X 0 ∆G = ∆Gf (products) − ∆Gf (reactants) 0 0 ∆Gf = ∆G of formation Free energy changes 0 −1 0 −1 Compound ∆Gf (kJ mol ) Compound ∆Gf (kJ mol ) acetaldehyde 139.7 glyceraldehyde-3-phosphate2– 1285.6 acetate 369.2 H+ 0.0 a acetyl-CoA 374.1 H2 (g) 0.0 3– cis-aconitate 920.9 H2O (l) 237.2 3– CO2 (g) 394.4 isocitrate 1160.0 2– CO2 (aq) 386.2 a-ketoglutarate 798.0 – – HCO3 587.1 lactate 516.6 3– citrate 1166.6 l-malate2– 845.1 dihydroxyacetone2– 1293.2 OH– 157.3 ethanol 181.5 oxaloacetate2– 797.2 fructose 915.4 phosphoenolpyruvate3– 1269.5 2– fructose-6-phosphate 1758.3 2-phosphoglycerate3– 1285.6 4– fructose-1,6-bisphosphate 2600.8 3-phosphoglycerate3– 1515.7 2– fumarate 604.2 pyruvate– 474.5 a-d-glucose 917.2 succinate2– 690.2 2– glucose-6-phosphate 1760.3 succinyl-CoA 686.7a a for formation from free elements + free CoA Rewrien aer Voet, D., Voet, J.
Load more

Recommended publications
  • MITOCW | 20. Bioenergetics/Intro Pathways/Glycolysis I
    MITOCW | 20. Bioenergetics/Intro Pathways/Glycolysis I [SQUEAKING] [RUSTLING] [CLICKING] PROFESSOR: Today we're going to discuss bioenergetics, continue that discussion and use that as a transition into also beginning to see how that applies to understanding glycolysis, the pathway that allows glucose breakdown. So just as a reminder of a couple of the points that we discussed last time, so last time we discussed what makes reactions favorable. And so remember, you could have any reaction, A to B-- A to B could be a single step. A to B could be an entire pathway, all steps in the pathway, that whether or not that reaction or pathway happens is determined by thermodynamics. It's not determined by enzymes. Enzymes are important, of course, to control the rate of reactions so they may allow things to happen that otherwise wouldn't happen. But whether the reaction happens or not is determined by free energy. And so free energy, delta G, remember we discussed is the following relationship. So it's related to this constant delta G0 prime, which is related to the equilibrium constant for any pair of products and reactants as well as this formula rt times the log of the products over the reactants. And so remember this means that whether a reaction happens depends on the equilibrium constant, but it also depends on the actual conditions present. That is how much substrate and how much product is there. And so what this means is that biology can come up with ways by keeping the product concentrations low to do things that may move in the opposite direction of what you would predict from equilibrium.
    [Show full text]
  • Content of Adenosine Phosphates and Adenylate Energy Charge in Germinating Ponderosa Pine Seeds
    Plant Physiol. (1972) 50, 536-540 Content of Adenosine Phosphates and Adenylate Energy Charge in Germinating Ponderosa Pine Seeds Received for publication May 18, 1972 TE MAY CHING AND KIM K. CHING Crop Science Department and Forest Research Laboratory, Oregon State University, Corvallis, Oregon 97331 ABSTRACT seed germination; (b) whether the gametophyte tissue (food An average of 540 picomoles of total adenosine phosphates storage) has an energy level and energy charge differing from was found in the embryo of mature seeds of ponderosa pine that in the embryo and seedling that may explain their di- (Pinus ponderosa Laws.) and 1140 picomoles in the gameto- vergent metabolic activities; (c) whether a correlation between phyte. Adenylate energy charges were 0.44 and 0.26, respec- the biogenesis of organelles (11) and energy level and energy tively. After stratification, total adenosine phosphates increased charge exists in the gametophytic tissue; and (d) whether co- 7-fold and 6-fold in embryo and gametophyte, respectively, and niferous seeds follow a pattern of energy metabolism during energy charges rose to 0.85 and 0.75. During germination, total germination similar to the angiosperm seeds. adenosine phosphates increased to a 20-fold peak on the 9th day in gametophytic tissue, parallel with the peak of reserve MATERIALS AND METHODS regradation and organellar synthesis, and then decreased. In embryo and seedling, total adenosine phosphates elevated 80- Uniformly large sized ponderosa pine (Pinus ponderosa fold with two distinct oscillating increases of AMP and ADP. Laws.) seeds were selected from a composite, highly viable lot The oscillating increases occurred before the emergence of of collections for 1970.
    [Show full text]
  • PAPER Role of Energy Charge and AMP-Activated Protein Kinase in Adipocytes in the Control of Body Fat Stores
    International Journal of Obesity (2004) 28, S38–S44 & 2004 Nature Publishing Group All rights reserved 0307-0565/04 $30.00 www.nature.com/ijo PAPER Role of energy charge and AMP-activated protein kinase in adipocytes in the control of body fat stores M Rossmeisl1, P Flachs1, P Brauner1, J Sponarova1, O Matejkova1, T Prazak1, J Ruzickova1, K Bardova1, O Kuda1 and J Kopecky1* 1Department of Adipose Tissue Biology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic As indicated by in vitro studies, both lipogenesis and lipolysis in adipocytes depend on the cellular ATP levels. Ectopic expression of mitochondrial uncoupling protein 1 (UCP1) in the white adipose tissue of the aP2-Ucp1 transgenic mice reduced obesity induced by genetic or dietary manipulations. Furthermore, respiratory uncoupling lowered the cellular energy charge in adipocytes, while the synthesis of fatty acids (FA) was inhibited and their oxidation increased. Importantly, the complex metabolic changes triggered by ectopic UCP1 were associated with the activation of AMP-activated protein kinase (AMPK), a metabolic master switch, in adipocytes. Effects of several typical treatments that reduce adiposity, such as administration of leptin, b-adrenoceptor agonists, bezafibrate, dietary n-3 polyunsaturated FA or fasting, can be compared with a phenotype of the aP2-Ucp1 mice. These situations generally lead to the upregulation of mitochondrial UCPs and suppression of the cellular energy charge and FA synthesis in adipocytes. On the other hand, FA oxidation is increased. Moreover, it has been shown that AMPK in adipocytes can be activated by adipocyte-derived hormones leptin and adiponectin, and also by insulin-sensitizes thiazolidinediones.
    [Show full text]
  • Alterations in Adenosine Triphosphate and Energy Charge in Cultured Endothelial and P388D1 Cells After Oxidant Injury
    Alterations in adenosine triphosphate and energy charge in cultured endothelial and P388D1 cells after oxidant injury. R G Spragg, … , I U Schraufstätter, C G Cochrane J Clin Invest. 1985;76(4):1471-1476. https://doi.org/10.1172/JCI112126. Research Article To investigate mechanisms whereby oxidant injury of cells results in cell dysfunction and death, cultured endothelial cells or P388D1 murine macrophage-like cells were exposed to oxidants including H2O2, O2-. (generated by the enzymatic oxidation of xanthine), or to stimulated polymorphonuclear leukocytes (PMN). Although Trypan Blue exclusion was not diminished before 30 min, cellular ATP was found to fall to less than 30% of control values within 3 min of exposure to 5 mM H2O2. Stimulated PMN plus P388D1 caused a 50% fall in cellular ATP levels. During the first minutes of oxidant injury, total adenylate content of cells fell by 85%. Cellular ADP increased 170%, AMP increased 900%, and an 83% loss of ATP was accompanied by a stoichiometric increase in IMP and inosine. Calculated energy charge [(ATP + 1/2 AMP)/(ATP + ADP + AMP)] fell from 0.95 to 0.66. Exposure of P388D1 to oligomycin plus 2-deoxyglucose (which inhibit oxidative and glycolytic generation of ATP, respectively) resulted in a rate of ATP fall similar to that induced by H2O2. In addition, nucleotide alterations induced by exposure to oligomycin plus 2-deoxyglucose were qualitatively similar to those induced by the oxidant. Loss of cell adenylates could not be explained by arrest of de novo purine synthesis or increased ATP consumption by the Na+-K+ ATPase or the mitochondrial F0-ATPase.
    [Show full text]
  • AMP-Activated Protein Kinase (AMPK) Action in Skeletal Muscle Via Direct Phosphorylation of PGC-1␣
    AMP-activated protein kinase (AMPK) action in skeletal muscle via direct phosphorylation of PGC-1␣ Sibylle Ja¨ ger, Christoph Handschin*, Julie St.-Pierre†, and Bruce M. Spiegelman‡ Dana–Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School, Boston, MA 02115 Contributed by Bruce M. Spiegelman, June 6, 2007 (sent for review March 28, 2007) Activation of AMP-activated kinase (AMPK) in skeletal muscle Several in vivo studies using AICAR to activate AMPK chronically increases glucose uptake, fatty acid oxidation, and mitochondrial determined that mitochondrial enzymes [e.g., cytochrome c, un- biogenesis by increasing gene expression in these pathways. coupling protein 3 (UCP-3)] (15–18) and proteins involved in However, the transcriptional components that are directly tar- glucose uptake (GLUT4) (18–20) are increased at the transcrip- geted by AMPK are still elusive. The peroxisome-proliferator- tional level in skeletal muscle. Interestingly, these genes are also ␥ activated receptor ␥ coactivator 1␣ (PGC-1␣) has emerged as a downstream targets of proliferator-activated receptor coactivator ␣ ␣ master regulator of mitochondrial biogenesis; furthermore, it has 1 (PGC-1 ), a highly regulated coactivator of nuclear receptors ␣ and many other transcription factors outside of the nuclear receptor been shown that PGC-1 gene expression is induced by exercise ␣ and by chemical activation of AMPK in skeletal muscle. Using family (21). PGC-1 is a key player in the oxidative metabolism of brown fat and muscle by increasing mitochondrial biogenesis and primary muscle cells and mice deficient in PGC-1␣, we found that augmenting the expression of enzymes of the electron transport the effects of AMPK on gene expression of glucose transporter 4, ␣ system and uncoupling proteins (22, 23).
    [Show full text]
  • Catalytic Potential and Disturbance Rejection of Glycolytic Kinases in the Human Red Blood Cell
    bioRxiv preprint doi: https://doi.org/10.1101/227058; this version posted November 30, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Catalytic potential and disturbance rejection of glycolytic kinases in the human red blood cell James T. Yurkovich1;2;y, Miguel A. Alcantar1;y, Zachary B. Haiman1, Bernhard O. Palsson1;2;3;∗ Abstract— The allosteric regulation of metabolic enzymes methods have been developed that allow for the study plays a key role in controlling the flux through metabolic of system dynamics [6]–[8]. Kinetic models represent an pathways. The activity of such enzymes is traditionally de- approach that has the potential to truly capture the temporal scribed by allosteric rate laws in complex kinetic models of metabolic network function. As an alternative, we describe the dynamics at small time scales [9]. The first whole-cell kinetic fraction of the regulated enzyme that is in an active form by model of RBC metabolism was published in the late 1980s developing a detailed reaction network of all known ligand [10]–[13], with other such models produced since then [14], binding events to the enzyme. This fraction is the fundamental [15]. More recently, enzyme modules have been introduced result of metabolic regulation as it represents the “tug of war” and used to explicitly model detailed binding events of among the various regulators and substrates that determine the utilization of the enzyme.
    [Show full text]
  • Functions of Maize Genes Encoding Pyruvate Phosphate Dikinase in Developing Endosperm
    Functions of maize genes encoding pyruvate phosphate dikinase in developing endosperm Ryan R. Lappea, John W. Baierb, Susan K. Boehleinb, Ryan Huffmanc, Qiaohui Lina, Fabrice Wattebledd, A. Mark Settlesb, L. Curtis Hannahb, Ljudmilla Borisjuke, Hardy Rolletscheke, Jon D. Stewartf, M. Paul Scottc,g, Tracie A. Hennen-Bierwagena, and Alan M. Myersa,1 aRoy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011; bHorticultural Sciences Department, University of Florida, Gainesville, FL 32611; cDepartment of Agronomy, Iowa State University, Ames, IA 50011; dUnivérsité de Lille, CNRS, UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, F 59000 Lille, France; eDepartment of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gaterslaben, Germany; fDepartment of Chemistry, University of Florida, Gainesville, FL 32611; and gCorn Insects and Crop Genetics Unit, US Department of Agriculture-Agricultural Research Service, Ames, IA 50011 Edited by Brian A. Larkins, University of Nebraska, Lincoln, NE, and approved November 27, 2017 (received for review September 7, 2017) Maize opaque2 (o2) mutations are beneficial for endosperm nutri- leaves, converting pyruvate from amino acid breakdown to PEP tional quality but cause negative pleiotropic effects for reasons that in a pathway yielding glutamine for amino group transport (13). are not fully understood. Direct targets of the bZIP transcriptional This involves cytosolic PPDK, rather than the plastidial form regulator encoded by o2 include pdk1 and pdk2 that specify pyru- involved in C4 metabolism. Cytosolic PPDK also functions in vate phosphate dikinase (PPDK). This enzyme reversibly converts gluconeogenesis during Arabidopsis seed germination, using py- AMP, pyrophosphate, and phosphoenolpyruvate to ATP, orthophos- ruvate from amino acid catabolism (14).
    [Show full text]
  • ADENYLATE ENERGY CHARGE AS a TOOL for EVALUATING SUB-LETHAL TOXICITY By
    QatarUniv. Sci J. (1999), 19: ADENYLATE ENERGY CHARGE AS A TOOL FOR EVALUATING SUB-LETHAL TOXICITY By.. Picado A. and LeGal Y. Yves LeGal: Laboratoire de Biologie Marine Museum National d'Histoire Naturelle et College de France, 29900 Concarneau, France; Tel. 33 (0)2 98 97 06 59, Fax 33 (0)2 98 97 81 24, E-mail: [email protected]) Running Title : Adenylate energy charge and sub-lethal toxicity SUMMARY Adenylate energy charge (AEC) is directly related to the cellular concentrations of the three adenylates nucleotides ATP, ADP and AMP. This biochemical index reaches high values (0.9) under optimal conditions but drops rapidly in the presence of stressing agents. In vertebrates, AEC is strongly regulated and maintained within narrow limits. In contrast, in invertebrates, AEC displays a wide range of values according to the importance of the internal stress or to the variations in the external environment of the organisms (natural or anthropogenic). This work concerns the use of adenine nucleotides concentrations, ATP/ ADP ratios and AEC as physiological markers in different species. Our results show that AEC is modified in animals submitted to experimental pollution or sampled in polluted areas. Results of zinc contamination in adults of clam Ruditapes decussatus show that after one month exposure, AEC values change significantly. The use of AEC in the bivalve Ruditapes decussatus for in situ evaluation allowed a classification among different sampling sites in what concerns environmental quality. In this way, AEC proved to be an accurate bi<?chemical and physiological marker in monitoring the health of organisms exposed to pollution and can be used as a complementary tool in impact and environmental management studies.
    [Show full text]
  • Glucose Availability but Not Changes in Pancreatic Hormones Sensitizes Hepatic AMPK Activity During Nutritional Transition in Rodents
    JBC Papers in Press. Published on March 17, 2020 as Manuscript RA119.010244 The latest version is at https://www.jbc.org/cgi/doi/10.1074/jbc.RA119.010244 Glucose availability but not changes in pancreatic hormones sensitizes hepatic AMPK activity during nutritional transition in rodents Camille Huet1, Nadia Boudaba1, Bruno Guigas2, Benoit Viollet1, and Marc Foretz1* From the 1Université de Paris, Institut Cochin, CNRS, INSERM, F-75014 Paris, France and 2Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands. Running title: Hepatic AMPK regulation during nutritional transition *To whom correspondence should be addressed: Marc Foretz, Institut Cochin, Département d’Endocrinologie Métabolisme et Diabète, 24, rue du Faubourg Saint-Jacques, 75014 Paris, France. Phone: 33.1.44.41.24.38; Fax: 33.1.44.41.24.21; email: [email protected] Keywords: AMP‐activated kinase (AMPK), glucose, insulin, glucagon, nutritional transition, metabolic regulation, energy homeostasis, nutrient sensing, metformin, liver, hepatocyte Downloaded from Abstract charge. Our results suggest that nutritional changes (i.e. glucose availability), rather than The cellular energy sensor AMP-activated the related hormonal changes (i.e. the protein kinase (AMPK) is a metabolic glucagon:insulin ratio), sensitize AMPK regulator that mediates adaptation to activation to the energetic stress induced by the http://www.jbc.org/ nutritional variations in order to maintain a dietary transition during fasting. This effect is proper energy balance in cells. We show here critical for preserving the cellular energy state that suckling-weaning and fasting-refeeding in the liver. transitions in rodents are associated with changes in AMPK activation and the cellular by guest on March 18, 2020 energy state in the liver.
    [Show full text]
  • Carbohydrate Metabolism Are Discussed
    08-McKee-Chap08.qxd:08-McKee-Chap08.qxd 1/13/11 9:38 PM Page 1 Carbohydrate CHAPTER 8 Metabolism OUTLINE METABOLISM AND JET ENGINES 8.1 GLYCOLYSIS The Reactions of the Glycolytic Pathway The Fates of Pyruvate The Energetics of Glycolysis Regulation of Glycolysis 8.2 GLUCONEOGENESIS Gluconeogenesis Reactions Gluconeogenesis Substrates Gluconeogenesis Regulation 8.3 THE PENTOSE PHOSPHATE PATHWAY 8.4 METABOLISM OF OTHER IMPORTANT SUGARS Fructose Metabolism 8.5 GLYCOGEN METABOLISM Glycogenesis Glycogenolysis Regulation of Glycogen Metabolism BIOCHEMISTRY IN PERSPECTIVE Saccharomyces Cerevisiae and the Crabtree Effect BIOCHEMISTRY IN PERSPECTIVE Turbo Design Can Be Dangerous Available online BIOCHEMISTRY IN PERSPECTIVE Fermentation: An Ancient Heritage Wine: A Product of Fermentation Humans use microorganisms, in this case yeast, to metabolize sugar in the absence of oxygen. The aging of wine in oak barrels improves its taste and aroma. 1 08-McKee-Chap08.qxd:08-McKee-Chap08.qxd 1/13/11 6:40 PM Page 2 Metabolism and Jet Engines an systems biology improve our understand- the end of the pathway) to run thermodynamically Cing of biochemical pathways such as glycolysis? downhill. As a result, the pathway can produce ATP Modern species are the result of billions of years of under varying substrate and product concentra- rigorous natural selection, which has adapted tions. The term “turbo design,” inspired by the organisms to their various environments. This turbo engines in jet aircraft, describes this selection process also governs the metabolic path- phenomenon. A good example is glycolysis, the ways that manage the biochemical transformations energy-capturing reaction pathway that converts that sustain life.
    [Show full text]
  • 11 12 13 TCA Cycle Laptop
    BI/CH 422/622 OUTLINE: Announcements: Glycogenolysis Exam 1 is posted. Grades were posted Glycolysis last night via Gradescope, which Other sugars has you ID# so that you can look at Pasteur: Anaerobic vs Aerobic whole class on the website. Fermentations Exam-1 material You have one week from return of grades for any changes, as usual. Pyruvate Exam-2 material pyruvate dehydrogenase These are submitted through Krebs’ Cycle Gradescope. How did he figure it out? Overview 8 Steps Citrate Synthase Aconitase Isocitrate dehydrogenase Ketoglutarate dehydrogenase Succinyl-CoA synthetase Succinate dehydrogenase Fumarase Malate dehydrogenase Energetics Regulation Summary The Citric Acid Cycle: Succinyl-CoA Synthetase • This step was not appreciated in original cycle until discover of CoA and its role (Fritz Lipmann). Named for the reverse reaction. • Substrate-level phosphorylation (like GAPDH + 1,3-BPG kinase) • The energy of thioester allows for incorporation of inorganic phosphate. • Goes through a phospho-enzyme intermediate • Produces GTP, which can be converted to ATP • Slightly thermodynamically favorable/reversible (DG°’ = –0.7 kcal/mol). – product concentration kept low to pull forward (OMSGAP) 1 The Citric Acid Cycle: Succinyl-CoA Synthetase Mechanism Phosphorolysis: Thioester to mixed Phospho-His anhydride; transfer to NDP; uphill energetically slightly downhill energetically Phosphoryl transfer to His; downhill energetically The Citric Acid Cycle: Succinyl-CoA Synthetase Mechanism Phosphorolysis: Thioester to mixed Phospho-His anhydride;
    [Show full text]
  • Pyruvate Cycle Increases Aminoglycoside Efficacy And
    Correction MICROBIOLOGY Correction for “Pyruvate cycle increases aminoglycoside efficacy and provides respiratory energy in bacteria,” by Yu-bin Su, Bo Peng, Hui Li, Zhi-xue Cheng, Tian-tuo Zhang, Jia-xin Zhu, Dan Li, Min-yi Li, Jin-zhou Ye, Chao-chao Du, Song Zhang, Xian-liang Zhao, Man-jun Yang, and Xuan-xian Peng, which was first pub- lished January 30, 2018; 10.1073/pnas.1714645115 (Proc Natl Acad Sci USA 115:E1578–E1587). The authors note that, in footnote 2 on page E1578, the email “[email protected]” should instead appear as “pengb26@sysu. edu.cn.” The authors also note that, on page E1580, right column, first full paragraph, line 6, “H2O” should instead appear as “2H2O” and “3CO2” should instead appear as “4CO2.” The authors note that Fig. 2 appeared incorrectly. The corrected figure and its legend appear below. 2774–2775 | PNAS | February 12, 2019 | vol. 116 | no. 7 www.pnas.org Downloaded by guest on September 29, 2021 CORRECTION Fig. 2. The P cycle and the TCA cycle in E. tarda.(A) Overview of the P cycle. Black line, overlapped pathway between the P cycle and the TCA; blue, a step of the TCA cycle, which does not exist in the P cycle; and red, pathways of the P cycle, which do not exist in the TCA cycle. ACO, aconitase; CS, citrate synthase; FUM, fumarase; GPT, glutamic-pyruvic transaminase; ICDH, isocitric dehydrogenase; MAE, malic enzyme (NAD-dependent malic enzyme and NADP- dependent malic enzyme); MDH, malate dehydrogenase; OGDH, α-oxoglutarate dehydrogenase; OXD, oxaloacetate decarboxylase; PDH, pyruvate de- hydrogenase; PEPC, phosphoenolpyruvate carboxylase; PEPCK, phosphoenolpyruvate carboxykinase; PFO, pyruvate-flavodoxin oxidoreductase; PK, pyruvate kinase; SCS, succinyl-CoA synthetase; and SDH, succinic dehydrogenase.
    [Show full text]