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Effects of elevated seawater pCO(2) on gene expression patterns in the gills of the green crab, Carcinus maenas. BMC Genomics 2011; 12:488. [PMID: 21978240 PMCID: PMC3206878 DOI: 10.1186/1471-2164-12-488] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 10/06/2011] [Indexed: 11/10/2022] Open
Abstract
Background The green crab Carcinus maenas is known for its high acclimation potential to varying environmental abiotic conditions. A high ability for ion and acid-base regulation is mainly based on an efficient regulation apparatus located in gill epithelia. However, at present it is neither known which ion transport proteins play a key role in the acid-base compensation response nor how gill epithelia respond to elevated seawater pCO2 as predicted for the future. In order to promote our understanding of the responses of green crab acid-base regulatory epithelia to high pCO2, Baltic Sea green crabs were exposed to a pCO2 of 400 Pa. Gills were screened for differentially expressed gene transcripts using a 4,462-feature microarray and quantitative real-time PCR. Results Crabs responded mainly through fine scale adjustment of gene expression to elevated pCO2. However, 2% of all investigated transcripts were significantly regulated 1.3 to 2.2-fold upon one-week exposure to CO2 stress. Most of the genes known to code for proteins involved in osmo- and acid-base regulation, as well as cellular stress response, were were not impacted by elevated pCO2. However, after one week of exposure, significant changes were detected in a calcium-activated chloride channel, a hyperpolarization activated nucleotide-gated potassium channel, a tetraspanin, and an integrin. Furthermore, a putative syntaxin-binding protein, a protein of the transmembrane 9 superfamily, and a Cl-/HCO3- exchanger of the SLC 4 family were differentially regulated. These genes were also affected in a previously published hypoosmotic acclimation response study. Conclusions The moderate, but specific response of C. maenas gill gene expression indicates that (1) seawater acidification does not act as a strong stressor on the cellular level in gill epithelia; (2) the response to hypercapnia is to some degree comparable to a hypoosmotic acclimation response; (3) the specialization of each of the posterior gill arches might go beyond what has been demonstrated up to date; and (4) a re-configuration of gill epithelia might occur in response to hypercapnia.
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Van Schaftingen E. Fructose 2,6-bisphosphate. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 59:315-95. [PMID: 3028056 DOI: 10.1002/9780470123058.ch7] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Simpfendörfer RW, Oelckers KB, López DA. Phosphofructokinase from muscle of the marine giant barnacle Austromegabalanus psittacus: kinetic characterization and effect of in vitro phosphorylation. Comp Biochem Physiol C Toxicol Pharmacol 2006; 142:382-389. [PMID: 16464641 DOI: 10.1016/j.cbpc.2005.11.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Revised: 11/22/2005] [Accepted: 11/25/2005] [Indexed: 11/26/2022]
Abstract
The kinetic properties of phosphofructokinase from muscle of the giant cirripede Austromegabalanus psittacus were characterized, after partial purification by ion exchange chromatography on DEAE-cellulose. This enzyme showed differences regarding PFKs from other marine invertebrates: the affinity for fructose 6-phosphate (Fru 6-P) was very low, with an S(0.5) of 22.6+/-1.4 mM (mean+/-S.D., n=3), and a high cooperativity (n(H) of 2.90+/-0.21; mean+/-S.D., n=3). The barnacle PFK showed hyperbolic saturation kinetics for ATP (apparent K(m ATP)=70 microM, at 5 mM Fru 6-P, in the presence of 2 mM ammonium sulfate). ATP concentrations higher than 1 mM inhibited the enzyme. Ammonium sulfate activated the PFK several folds, increasing the affinity of the enzyme for Fru 6-P and V(max). 5'-AMP (0.2 mM) increased the affinity for Fru 6-P (S(0.5) of 6.2 mM). Fructose 2,6-bisphosphate activated the PFK, with a maximal activation at concentrations higher than 2 microM. Citrate reverted the activation of PFK produced by 0.2 mM 5'-AMP (IC(50 citrate)=2.0 mM), producing a higher inhibition than that exerted on other invertebrate PFKs. Barnacle muscular PFK was activated in vitro after exposure to exogenous cyclic-AMP (0.1 mM) as well as by phosphatidylserine (50 microg/ml), indicating a possible control by protein kinase A and a phospholipid dependent protein kinase (PKC). The results suggest a highly regulated enzyme in vivo, by allosteric mechanisms and also by protein phosphorylation.
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Affiliation(s)
- Robert W Simpfendörfer
- Departamento de Acuicultura y Recursos Acuáticos, Universidad de Los Lagos, Casilla 933, Osorno, Chile.
| | - Karin B Oelckers
- Departamento de Acuicultura y Recursos Acuáticos, Universidad de Los Lagos, Casilla 933, Osorno, Chile
| | - Daniel A López
- Departamento de Acuicultura y Recursos Acuáticos, Universidad de Los Lagos, Casilla 933, Osorno, Chile
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Brooks SP, Storey KB. Glycolytic controls in estivation and anoxia: a comparison of metabolic arrest in land and marine molluscs. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART A, PHYSIOLOGY 1997; 118:1103-14. [PMID: 9505420 DOI: 10.1016/s0300-9629(97)00237-5] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Facultative metabolic rate depression is the common adaptive strategy underlying various animal mechanisms for surviving harsh environmental conditions. This strategy is common among molluscs, enabling animals to survive over days or even months in the absence of oxygen or under extremely dry conditions. The large reductions in metabolic rate during estivation and anoxia can translate into considerable energy savings when dormant animals are compared to active animals. A complex metabolic coordination is required during the transition into the dormant state to maintain cellular homeostasis and involves both energy-consuming and energy-producing pathways. With regard to energy-producing pathways, several different mechanisms have been identified that participate in controlling flux. One such mechanism, enzyme phosphorylation, can have a wide-ranging effect. For example, phosphorylated enzymes exhibit altered substrate, activator, and inhibitor affinities. This effect may be magnified by changes in the concentrations of allosteric effectors, such as fructose 2,6-bisphosphate, that occur during hypometabolic states. Changes in fructose 2,6-bisphosphate are related to changes in enzyme phosphorylation through changes in the relative activity of phosphofructokinase-2. Alterations in glycolytic enzyme binding can also be brought about through changes in enzyme phosphorylation. The present review focuses on identifying hypometabolism-related changes in enzyme phosphorylation as well as characterizing the mechanisms involved in mediating these phosphorylation events.
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Affiliation(s)
- S P Brooks
- Nutrition Research Division, Health Canada, Ottawa, Ontario, Canada
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Soukri A, Valverde F, Hafid N, Elkebbaj MS, Serrano A. Occurrence of a differential expression of the glyceraldehyde-3-phosphate dehydrogenase gene in muscle and liver from euthermic and induced hibernating jerboa (Jaculus orientalis). Gene 1996; 181:139-45. [PMID: 8973322 DOI: 10.1016/s0378-1119(96)00494-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A cDNA clone which contains the near-complete open reading frame (ORF) encoding glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) was obtained by screening a muscle cDNA library of jerboa (Jaculus orientalis), a true hibernating rodent, with a PCR-amplified 0.5-kb genomic DNA probe from an internal region of the gene. The 1.1-kb cDNA clone consists of a 927-bp ORF which codifies for 309 aa, about 93% of the original GapC gene encoding the 36-kDa protein, and a 3'-noncoding region of 167 bp. The full-length aa sequence of GAPDH was achieved by sequencing the N-terminal region of the purified protein completing the missing part in the cDNA clone. Both nt and aa sequences exhibit a high degree of homology to other mammalian GAPDHs. The expression of the GapC gene was studied in skeletal muscle and liver of euthermic and hibernating jerboas both on the mRNA level by Northern blot hybridization using the cDNA clone as a probe and on the protein level by Western blot immunodetection using an antibody raised against muscle GAPDH. A clear decrease (about threefold) in the amount of GapC mRNA, a single 1.2-kb transcript, was observed in muscle of hibernating jerboa when compared with the same tissue from the euthermic animal. This mRNA level decrease directly correlates with a reduction in both protein amount and specific activity in crude protein extracts. In contrast, both GAPDH protein and GapC mRNA levels remained unchanged in liver from euthermic and hibernating jerboas although the enzymatic activity was also about threefold lower in the hibernating tissue. These result, together with previous data obtained from protein studies [Soukri et al. (1995) Biochim. Biophys. Acta 1243, 161-168 and (1996) 1292, 177-187] indicate that jerboa GAPDH is regulated by different mechanisms during hibernation in these tissues, that is, at transcriptional level in muscle and at posttranslational level in liver. The reduced GAPDH activity should result in both cases in a decrease of the glycolytic flux that would eventually contribute to the dramatic metabolic depression of this dormant state.
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Affiliation(s)
- A Soukri
- Laboratoire de Biochimie, Biologie Cellulaire et Moléculaire, Faculté des Sciences-Ain Chock, Casablanca, Morocco
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Abstract
The existence and the regulatory mechanisms of the Pasteur effect in facultative anaerobic metazoa are discussed. There are three reasons for the controversy surrounding this phenomenon. 1) The different definitions of the Pasteur effect, 2) the antagonistic effect of metabolic depression and its species specific response to hypoxia, as well as 3) the laboratory-specific differences in the experimental procedures for analyzing the Pasteur effect and its regulation. This review aims to clarify the confusion about the existence of the Pasteur effect in facultative anaerobic metazoa and to offer possible molecular mechanisms.
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Affiliation(s)
- H Schmidt
- Institut für Tierphysiologie, Freie Universität Berlin, Germany
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Phosphofructokinase from the posterior gills of the euryhaline crab, Eriocheir sinensis: evidence for its regulation by phosphorylation. J Comp Physiol B 1994. [DOI: 10.1007/bf00301660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Grieshaber MK, Hardewig I, Kreutzer U, Pörtner HO. Physiological and metabolic responses to hypoxia in invertebrates. Rev Physiol Biochem Pharmacol 1993; 125:43-147. [PMID: 7984874 DOI: 10.1007/bfb0030909] [Citation(s) in RCA: 177] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- M K Grieshaber
- Institut für Zoologie, Heinrich-Heine-Universität, Düsseldorf, Germany
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Brooks SPJ, Storey KB. Properties of Pyruvate Dehydrogenase from the Land Snail, Otala lactea: Control of Enzyme Activity during Estivation. ACTA ACUST UNITED AC 1992. [DOI: 10.1086/physzool.65.3.30157973] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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The role of phosphofructokinase in glycolytic control in the facultative anaerobe Sipunculus nudus. J Comp Physiol B 1991. [DOI: 10.1007/bf00260748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lazou A. Regulation of phosphofructokinase in the foot muscle ofPatella caerulea (L.) during exposure to air. ACTA ACUST UNITED AC 1991. [DOI: 10.1002/jez.1402590209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Biethinger M, Hoffmann R, Hofer HW. Phosphofructokinase from mollusc muscle is activated by phosphorylation. Arch Biochem Biophys 1991; 287:263-7. [PMID: 1654810 DOI: 10.1016/0003-9861(91)90477-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Phosphofructokinase was purified from muscle tissue of two different molluscs, edible snails, Helix pomatia (gastropoda), and mussels, Mytilus edulis (bivalvia). Under denaturing conditions, both enzymes had a molecular mass of 82 kDa. In the presence of ATP-Mg2+, the enzymes were rapidly phosphorylated in vitro by the catalytic subunit of cyclic AMP (cAMP)-dependent protein kinase purified from snail muscle and also by the C subunit of protein kinase from bovine heart. The extent of phosphorylation was 0.6 and 0.5 phosphate residues per subunit for the snail and the mussel phosphofructokinase, respectively. Phosphorylation of both phosphofructokinases effected a decrease in ATP inhibition at neutral or slightly acidic pH values and increased the affinity for fructose 6-phosphate. The resulting activation in the presence of suboptimum fructose 6-phosphate concentrations was more distinct for the snail enzyme. In addition, phosphorylated phosphofructokinase from mussels exhibited a marked increase in Vmax when activated by either 5'-AMP or fructose 2,6-bisphosphate.
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Affiliation(s)
- M Biethinger
- Faculty of Biology, University of Konstanz, Germany
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Brooks SP, Storey KB. The role of protein kinases in anoxia tolerance in facultative anaerobes: purification and characterization of a protein kinase that phosphorylates pyruvate kinase. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1073:253-9. [PMID: 2009278 DOI: 10.1016/0304-4165(91)90129-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A protein kinase which phosphorylates pyruvate kinase (PK) in vitro was purified and characterized from the foot muscle of the anoxia-tolerant gastropod mollusc Busycon canaliculatum. Purification involved four steps: poly(ethylene glycol) fractionation, affinity chromatography on Blue agarose, ion-exchange chromatography on phosphocellulose and preparative isoelectric focusing (pI = 5.5). The activity was monitored by following changes in pyruvate kinase I50 values for L-alanine which have previously been linked to changes in the degree of enzyme phosphorylation. The correlation between enzyme phosphorylation and changes in the L-alanine inhibition constant was also directly demonstrated in the present paper by radioactively labelling PK with [tau-32P]ATP. The final purified protein kinase solution gave a single band on SDS-gel electrophoresis with a molecular weight of 37,000 +/- 2000. Kinetic analysis of the purified protein kinase (PK-kinase) showed a pH optimum of 7.0, an absolute requirement for magnesium ions (Km = 1.29 mM), a relatively high affinity for MgATP (Km = 57 microM), and inhibition by increasing salt concentrations (I50 = 55 mM KCl). The protein kinase activity was not affected by either spermine, heparin, cAMP, cGMP or concentrations of CaCl2 less than 10 mM. The enzyme did not phosphorylate either phosphofructokinase or glycogen phosphorylase, two enzymes that are also phosphorylated during anoxia in whelks. The purified enzyme is different from the catalytic subunit of cAMP-dependent protein kinase as shown by the inability of cAMP to stimulate the protein kinase at all stages of the preparation; cAMP did not activate either crude enzyme, the 7% poly(ethylene glycol) supernatant, or any of the column eluant peak fractions when measured by changes in pyruvate kinase kinetic parameters.
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Affiliation(s)
- S P Brooks
- Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
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Whitwam RE, Storey KB. Regulation of Phosphofructokinase during Estivation and Anoxia in the Land Snail, Otala lactea. ACTA ACUST UNITED AC 1991. [DOI: 10.1086/physzool.64.2.30158192] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Michaelidis B, Storey KB. Evidence for phosphorylation/dephosphorylation control of phosphofructokinase from organs of the Anoxia-Tolerant sea musselMytilus edulis. ACTA ACUST UNITED AC 1991. [DOI: 10.1002/jez.1402570102] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Juretschke HP, Kamp G. Influence of intracellular pH on reduction of energy metabolism during hypoxia in the lugwormArenicola marina. ACTA ACUST UNITED AC 1990. [DOI: 10.1002/jez.1402560304] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Michaelidis B, Storey KB. Anaerobiosis and the regulation of glycolytic enzymes in the sea anemoneMetridium senile. ACTA ACUST UNITED AC 1990. [DOI: 10.1002/jez.1402560205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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cGMP-stimulated protein kinase phosphorylates pyruvate kinase in an anoxia-tolerant marine mollusc. J Comp Physiol B 1990. [DOI: 10.1007/bf00302597] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Michaelidis B, Papadopoulos A, Beis I. Effect of anoxia on the kinetic properties of pyruvate kinase and phosphofructokinase, and on glycogen phosphorylase activity in marine worms and earth worms. J Comp Physiol B 1990. [DOI: 10.1007/bf00300954] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Michaelidis B, Storey KB. Influence of pH on the regulatory properties of aerobic and anoxic forms of pyruvate kinase in a marine whelk. ACTA ACUST UNITED AC 1990. [DOI: 10.1002/jez.1402530303] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Brooks SP, Storey KB. Phosphofructokinase from a vertebrate facultative anaerobe: effects of temperature and anoxia on the kinetic parameters of the purified enzyme from turtle white muscle. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1037:161-4. [PMID: 2137714 DOI: 10.1016/0167-4838(90)90162-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The effects of low temperature and anoxia were determined on phosphofructokinase (PFK) purified from white skeletal muscle of the freshwater turtle, Pseudemys scripta. These effects were assayed by comparing PFK kinetic constants measured at a high (20 degrees C) and low (6 degrees C) temperature using enzyme obtained from animals held under normoxic and anoxic conditions. When assayed at 20 degrees C, PFK from anoxic animals had a lower Ka for phosphate, a lower Ka for AMP and showed no inhibition with increasing concentrations of ATP (up to 10 mM) when compared to enzyme from normoxic animals. At 6 degrees C, anoxic enzyme had a higher Km for fructose 6-phosphate and a higher I50 value for citrate with respect to normoxic enzyme. Decreasing temperature also had a differential effect on PFK kinetic parameters depending on the source of the enzyme. When normoxic enzymes were compared at 20 and 6 degrees C, the enzyme measured at 6 degrees C showed a lower Km for ATP and a lower Ka for AMP. Comparison of anoxic enzymes at these two temperatures showed that anoxic PFK at 6 degrees C had a higher Ka for phosphate, a higher Ka for AMP, and a larger Hill coefficient. A comparison of maximal velocities at varying temperature showed that normoxic enzyme (Q10 = 2.22) was more temperature sensitive than the anoxic enzyme (Q10 = 1.80). It is possible to interconvert the normoxic and anoxic forms of PFK by incubating normoxic enzyme with the active subunit of protein kinase, suggesting that the kinetic changes observed during anoxia resulted from enzyme phosphorylation. These data are discussed with respect to the mechanisms underlying white muscle function during diving and hibernation in red-eared turtles.
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Affiliation(s)
- S P Brooks
- Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
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Michaelidis B, B. Storey K. Phosphofructokinase from the anterior byssus retractor muscle of Mytilvs edulis: Modification of the enzyme in anoxia and by endogenous protein kinases. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0020-711x(90)90012-r] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Activities of hexokinase, phosphofructokinase and pyruvate kinase in the body wall, pyloric caeca and tube feet of Asterias vulgaris: Evidence of body wall as a major source of glycolytic activity. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0305-0491(89)90343-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Brooks SP, Storey KB. Purification of phosphofructokinase using transition-state analogue affinity chromatography. J Chromatogr A 1988; 455:291-6. [PMID: 2976771 DOI: 10.1016/s0021-9673(01)82127-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A novel purification of phosphofructokinase has been achieved in a two step process using ion-exchange affinity chromatography and a transition-state analogue affinity column matrix. The procedure can be performed in one day, and gives a 25% yield of the starting material. The transition-state analogue chromatography is carried out using an ADP-agarose column in the presence of fructose 6-phosphate, magnesium ions and nitrate ions. In the presence of nitrate ion plus substrate, phosphofructokinase binds immobilized ADP while other proteins pass through the column. Previous studies with creatine kinase have shown that the nitrate ion mimics the planar phosphate in the transition state resulting in a complex which is stable under the relatively high ionic strength of the column buffer. This permits the elution of phosphofructokinase in a single peak of high specific activity. This column typically results in a 20-30 fold increase in specific activity with only a small loss of activity.
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Affiliation(s)
- S P Brooks
- Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
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Abstract
An examination of the kinetic parameters of phosphofructokinase, pyruvate kinase and glycogen phosphorylase, and the cellular concentration of fructose 2,6-bisphosphate during anoxia in the turtle Pseudemys scripta showed that the total activity of glycogen phosphorylase, and the phosphofructokinase inhibition constants for citrate and ATP were decreased in anoxic turtle brain. These results suggest that the ability of turtle brain to survive extended periods of anoxia is the result of metabolic rate depression regulated, at the molecular level, by enzyme inactivation through anoxia-induced covalent modification.
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Affiliation(s)
- S P Brooks
- Institute of Biochemistry, Carleton University Ottawa, Ontario, Canada
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Role of covalent modification in the control of glycolytic enzymes in response to environmental anoxia in goldfish. J Comp Physiol B 1988. [DOI: 10.1007/bf00691013] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Storey KB. Tissue-Specific Controls on Carbohydrate Catabolism during Anoxia in Goldfish. ACTA ACUST UNITED AC 1987. [DOI: 10.1086/physzool.60.5.30156134] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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