DOCSLIB.ORG

Effect of Thiamine Pyrophosphate on Ischemia-Reperfusion Induced Oxidative Damage in Rat Kidney

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Effect of Thiamine Pyrophosphate on Ischemia-Reperfusion Induced Oxidative Damage in Rat Kidney Research Article Effect of thiamine pyrophosphate on ischemia-reperfusion induced oxidative damage in rat kidney Durdu Altuner, Nihal Cetin, Bahadir Suleyman, Zeynep Aslan1, Ahmet Hacimuftuoglu1, Mine Gulaboglu2, Neslihan Isaoglu3, Ismail Demiryilmaz4, Halis Suleyman ABSTRACT Department of Pharmacology, Objectives: The biochemical effects of thiamine pyrophosphate on ischemia-reperfusion Faculty of Medicine, Recep Tayyip (IR) induced oxidative damage and DNA mutation in rat kidney tissue were investigated, Erdogan University, Rize, and compared to thiamine. 1 Department of Pharmacology, Materials and Methods: Rats were divided into four groups: Renal ischemia-reperfusion Faculty of Medicine and (RIR); thiamine pyrophosphate + RIR (TPRIR); thiamine + RIR (TRIR); and sham group (SG). 2Biochemistry, Faculty of Pharmacy, Results: The results of biochemical experiments have shown that malondialdehyde (MDA) Ataturk University, Erzurum, 3Department of Anesthesia, Nene levels in rat kidney tissue after TRIR and TPRIR treatment were 7.2 ± 0.5 (P > 0.05) and 3.3 Hatun Obstetrics and Gynecology ± 0.3 (P < 0.0001) µmol/g protein, respectively. The MDA levels in the SG rat kidney tissue Hospital, Erzurum, 4Department of and in RIR group were 3.6 ± 0.2 (P < 0.0001) and 7.6 ± 0.6 µmol/g protein, respectively. General Surgery, Ibni Sina Hospital, Total glutathione (tGSH) levels in TRIR, TPRIR, SG, and RIR animal groups were 2.2 ± 0.3 Kayseri, Turkey (P > 0.05), 5.8 ± 0.4 (P < 0.0001), 6.2 ± 0.2 (P < 0.0001), and 1.7 ± 0.2 nmol/g protein, respectively. In the TRIR, TPRIR, SG, and RIR animal groups; 8-hydroxyguanine (8-OHGua)/ Received: 05-06-2012 Gua levels, which indicate mutagenic DNA, were 1.75 ± 0.12 (P > 0.05), 0.93 ± 0.1 (P < Revised: 03-02-2013 0.0001), 0.85 ± 0.08 (P < 0.0001), and 1.93 ± 0.24 pmol/L, respectively. Accepted: 26-04-2013 Conclusions: It has been shown that thiamine pyrophosphate prevents increase in mutagenic DNA in IR induced oxidative damage, whereas thiamine does not have this Correspondence to: effect. Dr. Halis Suleyman, E-mail: [email protected] KEY WORDS: DNA mutation, ischemia-reperfusion, oxidative damage, rat, thiamine pyrophosphate Introduction malondialdehyde (MDA).[4] Furthermore, it has been reported that excessive free oxygen radicals react with DNA, causing Ischemia-reperfusion (IR) process, which is performed oxidative damage of DNA. This oxidative damage is characterized during kidney transplants and various urological procedures, by DNA breaks in base chains and ribose-phosphate bonds, as [1] leads to kidney damage. IR injury is a complex condition and is well as double strand breaks. The initial damage is caused the main cause of acute renal failure. As soon as reoxygenation by formation of pyrimidine dimers due to breaks in thymine- is achieved by reperfusion, the enzyme xanthine oxidase, which adenine bonds. After reaction with free oxygen radicals, is formed during ischemia[2] converts accumulated hypoxanthine base changes in nucleic acids and chain breaks in DNA are to xanthine, resulting in a large amount of free oxygen radicals encountered. If this damage cannot be repaired, DNA mutation in the environment.[3] The free oxygen radicals, which are called will follow. 8-hydroxyguanine (8-OHGua) is a mutagenic form reperfusion mediators, oxidate the cell membrane lipids and of DNA.[5] GSH and other antioxidants prevent harmful effects cause formation of toxic products, such as aldehydes and of free oxygen radicals on cellular structures, but when the antioxidant defense mechanisms fail, serious tissue damage [6] Access this article online occurs. This suggests that treatment with antioxidants may Quick Response Code: be beneficial in IR injury. Website: www.ijp-online.com Thiamine pyrophosphate, which we have used in our study DOI: 10.4103/0253-7613.115005 for treatment of IR injury, is an active metabolite of thiamine. Thiamine pyrophosphate is formed by phosphatizing of thiamine in the liver. Thiamine increases the formation of antioxidants and nicotineamide adenine dinucleotide phosphate (NADPH) levels via pentose phosphate pathway.[7] Because IR damage Indian Journal of Pharmacology | August 2013 | Vol 45 | Issue 4 339 Altuner, et al.: Thiamine pyrophosphate on IR in rat kidney is a rapidly developing process, thiamine pyrophosphate use, of TPRIR and TRIR groups were compared with results of the that its active metabolite, thought to be more effective. The RIR and SG groups. antioxidant properties of thiamine pyrophosphate is not yet Biochemical Analysis of Renal Tissue fully known. In recent years, studies have shown the antioxidant From each kidney, a sample of renal tissue of 0.2 g was activity of thiamine pyrophosphate. In a study, it was found that obtained. The samples were homogenized in ice with 2 ml IR induced oxidative damage in rat ovary was not prevented by of 1.15% potassium chloride buffer for MDA analysis and [8] thiamine, but it was prevented by thiamine pyrophosphate. In phosphate buffer with a pH of 7.5 for other analyses. Then, addition, unlike thiamine, thiamine pyrophosphate is a cofactor they were centrifuged at 4°C, 10,000 rpm for 15 min. The for both pyruvate-2-oxoglutarate dehydrogenase complex that supernatant was used as the analysis sample. For all the is required for mitochondrial adenosine triphosphate (ATP) measurements, the tissue-protein estimation was performed synthesis and transketolase enzyme plays an important role using Bradford’s method.[10] in maintaining cellular redox status.[9] Therefore, thiamine MDA Analysis pyrophosphate is important for cellular energy production and The concentrations of renal lipid peroxidation were preservation. In literature, we have not found any information determined by estimating MDA using thiobarbituric acid test.[11] about protective effect of thiamine pyrophosphate in IR induced The rat renal tissues were rinsed with cold saline. The corpus kidney injury in rats. The aim of our study was to investigate the mucosa was scraped, weighed, and homogenized in 10 ml of biochemical effects of thiamine pyrophosphate on IR induced 100 g/L KCl. The homogenate (0.5 ml) was added to a solution oxidative damage and DNA mutation in rat kidney tissue, and containing 0.2 ml of 80 g/L sodium lauryl sulfate, 1.5 mL of to compare it to that of thiamine. 200 g/L acetic acid, 1.5 mL of 8 g/L 2-thiobarbiturate, and Materials and Methods 0.3 mL distilled water. The mixture was incubated at 98°C for 1 h. Upon cooling, 5 ml of n-butanol:pyridine (15:l) was Animals added. The mixture was vortexed for 1 min and centrifuged In this study, 24 albino Wistar male rats of 230–245 g for 30 min at 4,000 rpm. The absorbance of supernatant was were used, which were supplied from Atatürk University measured at 532 nm. The standard curve was obtained by using Medical Application and Research Center. The animals were 1,1,3,3-tetramethoxypropane. kept in room temperature (22°C) in groups and were fed. In Total Glutathione (tGSH) Analysis document B.30.2.ATA.0.23.85-57 dated 5 April 2012, Atatürk The amount of GSH in the total homogenate was University Local Ethical Committee of Experimental Animals measured according to the method of Sedlak and Lindsay (AUDHADYEK) approved that all the steps of this study were with some modifications.[12] The sample was weighed and compliant with ethical rules. homogenized in 2 mL of 50 mM tris-HCl buffer containing 20 mM Chemicals ethylenediamineteraacetic acid (EDTA) and 0.2 mM sucrose at Thiopental sodium was provided by IE Ulagay, Turkey. pH 7.5. The homogenate was immediately precipitated with 0.1 Thiamine and thiamine pyrophosphate were obtained from mL of 25% trichloroacetic acid, and the precipitate was removed Biopharma, Russia. after centrifugation at 4,200 rpm for 40 min at 4°C and the General Procedure supernatant was used to determine GSH levels. A total of 1500 The rats were divided into four groups as follows: Renal µL of measurement buffer (200 mM tris-HCl buffer containing 0.2 ischemia-reperfusion group (RIR); thiamine pyrophosphate mM EDTA at pH 7.5), 500 µL supernatant, 100 µL 5,5-dithiobis + RIR group (TPRIR); thiamine + RIR group (TRIR), and sham (2-nitrobenzoic acid) (DTNB) (10 mM), and 7900 µl methanol group (SG). The surgical interventions on rats were performed in were added to a tube and vortexed and incubated for 30 min in laboratories, under sterile conditions, using thiopental sodium 37°C. DTNB was used as a chromogen and it formed a yellow- (25 mg/kg intraperitoneal (i.p.)) anesthesia. colored complex with sulfhydryl (SH) groups. The absorbance was Performing Study measured at 412 nm using a spectrophotometer. The standard An hour before the thiopental sodium anesthesia, TPRIR curve was obtained by using reduced GSH. group (n = 6) was given thiamine pyrophosphate 25 mg/kg Isolation of DNA from Renal Tissue i.p. and TRIR group was given thiamine 25 mg/kg i.p. In the DNA was isolated from renal tissue using Shigenaga RIR and SG groups, distilled water was injected via the same et al.’s, modified method.[13] The samples (for renal tissue way. After thiopental sodium injection, rats were kept until 50 mg) were homogenized at 4°C in 1 mL of homogenization appropriate moment for surgical intervention. The moment buffer (0.1 M NaCl, 30 mM Tris, pH 8.0, 10 mM EDTA, that animals remain motionless in supine position is considered 10 mM 2-mercaptoethanol, 0.5% (v/v) Triton X-100) with the appropriate time to perform surgery. The kidneys of rats six passes of a teflon glass homogenizer at 200 rpm. The were reached through a unilateral dorsal incision on the left samples were centrifuged at 4°C for 10 min at 1,000 g to side.
Load more

Recommended publications
  • The Influence of Vitamin B12on the Content, Distribution and in Vivo
    The Influence of Vitamin B12on the Content, Distribution and in Vivo Synthesis of Thiamine Pyrophosphate, Flavin Adenine Dinucleotide and Pyridine Nucleotides in Rat Liver1 URMILA MARFATIA, D. V. REGE, H. P. TIPNIS ANDA. SREENIVASAN Department of Chemical Technology, University of Bombay, Matunga, Bombay Apart from the well-known interrelation (FAD) and pyridine nucleotides (PN), and ships among the B vitamins, there is rea to their in vivo synthesis from the corre son to believe that folie acid and vitamin sponding administered vitamins, in the rat Downloaded from Bu may influence the functioning of other liver. Data on the distribution of these vitamins as cofactors. Thus, dietary folie cofactors in liver cells of the normal rat acid has been known to determine rat are available in the works of Goethart ('52) liver stores of coenzyme A (CoA) and and Dianzani and Dianzani Mor ('57) on adenotriphosphate (ATP) (Popp and Tot TPP, of Carruthers and Suntzeff ('54) and ter, '52; Totter, '53); a decrease in liver Dianzani ('55) on pyridine nucleotides DPN is also caused by aminopterin2 (PN) and of Schneider and Hogeboom jn.nutrition.org (Strength et al., '54). The in vivo incor (Schneider, '56) on FAD. poration of nitcotinamide into pyridino- nucleotides in rat liver is affected in a EXPERIMENTAL deficiency of vitamin B«(Nadkarni et al., Young, male Wistar rats weighing ap '57). Low blood level of citrovorum factor proximately 100 gm each were used. The by guest on April 19, 2011 in the hyperthyroid, vitamin Bi2-deficient animals, housed individually in raised rat is corrected by administration of vita mesh-bottom cages, were initially depleted min B«(Pfander et al., '52).
    [Show full text]
  • Roles of Vitamin Metabolizing Genes in Multidrug-Resistant Plasmids of Superbugs
    bioRxiv preprint doi: https://doi.org/10.1101/285403; this version posted March 20, 2018. 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 4.0 International license. Roles of Vitamin Metabolizing Genes in Multidrug-Resistant Plasmids of Superbugs Asit Kumar Chakraborty, Genetic Engineering Laboratory, Department of Biotechnology & Biochemistry, Oriental Institute of Science & Technology, Vidyasagar University, Midnapore 721102, West Bengal, India. Abstract Superbug crisis has rocked this world with million deaths due to failure of potent antibiotics. Thousands mdr genes with hundreds of mutant isomers are generated. Small integrons and R-plasmids have combined with F'-plasmids creating a space for >10-20 of mdr genes that inactivate antibiotics in different mechanisms. Mdr genes are created to save bacteria from antibiotics because gut microbiota synthesize >20 vitamins and complex bio-molecules needed for >30000 biochemical reactions of human metabolosome. In other words, mdr gene creation is protected from both sides, intestinal luminal cells and gut bacteria in a tight symbiotic signalling system. We have proposed, to avert the crisis all vitamin metabolizing genes will be acquired in MDR- plasmids if we continue oral antibiotics therapy. Therefore, we have checked the plasmid databases and have detected thiamine, riboflavin, folate, cobalamine and biotin metabolizing enzymes in MDR plasmids. Thus vit genes may mobilise recently into MDR-plasmids and are likely essential for gut microbiota protection. Analysis found that cob and thi genes are abundant and likely very essential than other vit genes.
    [Show full text]
  • Coenzymes and Prosthetic Groups Nomenclature
    Coenzymes and prosthetic groups Nomenclature • Cofactor: nonprotein component of enzymes • Cofactor - a co-catalyst required for enzyme activity • Coenzyme - a dissociable cofactor, usually organic • Prosthetic group - non-dissociable cofactor • Vitamin - a required micro-nutrient (organism cannot synthesize adequate quantities for normal health - may vary during life-cycle). – water soluble - not stored, generally no problem with overdose – lipid soluble - stored, often toxic with overdose. • Apoenzyme - enzyme lacking cofactor (inactive) • Holoenzyme - enzyme with cofactors (active) Vitamins are precursors of cofactors Why cofactors? Adenine Nucleotide Coenzymes All use the adenine nucleotide group solely for binding to the enzyme! • pyridine dinucleotides (NADH, NADPH) • flavin mono- and dinucleotides (FMN, FADH) • coenzyme A Nucleotide triphosphates • ATP hydrolysis – resonance stabilizes products – reactants cannot be resonance stabilized because of competition with adjacent bridging anhydrides – charge density greater on reactants than products Coenzyme A • Activation of acyl groups for transfer by nucleophilic attack • activation of the alpha- hydrogen of the acyl group for abstraction as a proton • Both these functions are mediated by the reactive -SH group on CoA, which forms thioesters Coenzyme A Nicotinic Acid/Nicotinamide Coenzymes • These coenzymes are two-electron carriers • They transfer hydride anion (H-) to and from substrates • Two important coenzymes in this class: • Nicotinamide adenine dinucleotide (NAD+) • Nicotinamide
    [Show full text]
  • The Biosynthesis of the Molybdenum Cofactor in Escherichia Coli and Its Connection to Fes Cluster Assembly and the Thiolation of Trna
    Hindawi Publishing Corporation Advances in Biology Volume 2014, Article ID 808569, 21 pages http://dx.doi.org/10.1155/2014/808569 Review Article The Biosynthesis of the Molybdenum Cofactor in Escherichia coli and Its Connection to FeS Cluster Assembly and the Thiolation of tRNA Silke Leimkühler Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany Correspondence should be addressed to Silke Leimkuhler;¨ [email protected] Received 16 January 2014; Accepted 28 March 2014; Published 29 April 2014 Academic Editor: Paul Rosch¨ Copyright © 2014 Silke Leimkuhler.¨ This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The thiolation of biomolecules is a complex process that involves the activation of sulfur. The L-cysteine desulfurase IscS is the main sulfur mobilizing protein in Escherichia coli that provides the sulfur from L-cysteine to several important biomolecules in the cell such as iron sulfur (FeS) clusters, molybdopterin (MPT), thiamine, and thionucleosides of tRNA. Various proteins mediate the transfer of sulfur from IscS to various biomolecules using different interaction partners. A direct connection between the sulfur- containing molecules FeS clusters, thiolated tRNA, and the molybdenum cofactor (Moco) has been identified. The first step of Moco biosynthesis involves the conversion of 5 GTP to cyclic pyranopterin monophosphate (cPMP), a reaction catalyzed by a FeS cluster containing protein. Formed cPMP is further converted to MPT by insertion of two sulfur atoms. The sulfur for this reaction is provided by the L-cysteine desulfurase IscS in addition to the involvement of the TusA protein.
    [Show full text]
  • Vitamins and Minerals for Energy, Fatigue and Cognition: a Narrative Review of the Biochemical and Clinical Evidence
    nutrients Review Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence Anne-Laure Tardy 1,*, Etienne Pouteau 1 , Daniel Marquez 2, Cansu Yilmaz 3 and Andrew Scholey 4 1 Sanofi Consumer Healthcare, Global Medical Nutritionals, 94250 Gentilly, France; Etienne.Pouteau@sanofi.com 2 Sanofi Consumer Healthcare, 04000 México City, Mexico; Daniel.Marquez@sanofi.com 3 Sanofi Consumer Healthcare, 34394 Be¸sikta¸sIstanbul, Turkey; cansu.yilmaz@sanofi.com 4 Centre for Human Psychopharmacology, Swinburne University, Victoria, VIC 3122, Australia; [email protected] * Correspondence: Anne-Laure.Tardy@sanofi.com Received: 23 December 2019; Accepted: 11 January 2020; Published: 16 January 2020 Abstract: Vitamins and minerals are essential to humans as they play essential roles in a variety of basic metabolic pathways that support fundamental cellular functions. In particular, their involvement in energy-yielding metabolism, DNA synthesis, oxygen transport, and neuronal functions makes them critical for brain and muscular function. These, in turn, translate into effects on cognitive and psychological processes, including mental and physical fatigue. This review is focused on B vitamins (B1, B2, B3, B5, B6, B8, B9 and B12), vitamin C, iron, magnesium and zinc, which have recognized roles in these outcomes. It summarizes the biochemical bases and actions of these micronutrients at both the molecular and cellular levels and connects them with cognitive and psychological symptoms, as well as manifestations of fatigue that may occur when status or supplies of these micronutrients are not adequate. Keywords: B vitamins; vitamin C; iron; magnesium; zinc; energy production; mental and physical fatigue; anemia; cognition; mood.
    [Show full text]
  • 1,2,3,5,6,8,10,11,16,20,21 Citric Acid Cycle Reactions
    Overview of the citric acid cycle, AKA the krebs cycle AKA tricarboxylic acid AKA TCA cycle Suggested problems from the end of chapter 19: 1,2,3,5,6,8,10,11,16,20,21 Glycogen is broken down into glucose. The reactions of glycolysis result in pyruvate, which is then fed into the citric acid cycle in the form of acetyl CoA. The products of the citric acid cycles are 2 CO2, 3 NADH, 1 FADH2, and 1 ATP or GTP. After pyruvate is generated, it is transported into the mitochondrion, an organelle that contains the citric acid cycle enzymes and the oxidative phosphorylation enzymes. In E. coli, where there are neither mitochondria nor other organelles, these enzymes also seem to be concentrated in certain regions in the cell. Citric acid cycle reactions Overall, there are 8 reactions that result in oxidation of the metabolic fuel. This results in reduction of NAD+ and FAD. NADH and FADH2 will transfer their electrons to oxygen during oxidative phosphorylation. •In 1936 Carl Martius and Franz Knoop showed that citrate can be formed non-enzymaticly from Oxaloacetate and pyruvate. •In 1937 Hans Krebs used this information for biochemical experiments that resulted in his suggestion that citrate is processed in an ongoing circle, into which pyruvate is “fed.” •In 1951 it was shown that it was acetyl Coenzyme-A that condenses with oxaloacetate to form citrate. 1 The pre-citric acid reaction- pyruvate dehydrogenase Pyruvate dehydrogenase is a multi-subunit complex, containing three enzymes that associate non-covalently and catalyze 5 reaction. The enzymes are: (E1) pyruvate dehydrogenase (E2) dihydrolipoyl transacetylase (E3) dihydrolipoyl dehydrogenase What are the advantages for arranging enzymes in complexes? E.
    [Show full text]
  • Assessing the Thiamine Diphosphate Dependent Pyruvate Dehydrogenase E1 Subunit for Carboligation Reactions with Aliphatic Ketoacids
    International Journal of Molecular Sciences Article Assessing the Thiamine Diphosphate Dependent Pyruvate Dehydrogenase E1 Subunit for Carboligation Reactions with Aliphatic Ketoacids Stefan R. Marsden, Duncan G. G. McMillan and Ulf Hanefeld * Biokatalyse, Afdeling Biotechnologie, Technische Universiteit Delft, Van der Maasweg 9, 2629HZ Delft, The Netherlands; [email protected] (S.R.M.); [email protected] (D.G.G.M.) * Correspondence: [email protected] Received: 12 October 2020; Accepted: 12 November 2020; Published: 16 November 2020 Abstract: The synthetic properties of the Thiamine diphosphate (ThDP)-dependent pyruvate dehydrogenase E1 subunit from Escherichia coli (EcPDH E1) was assessed for carboligation reactions with aliphatic ketoacids. Due to its role in metabolism, EcPDH E1 was previously characterised with respect to its biochemical properties, but it was never applied for synthetic purposes. Here, we show that EcPDH E1 is a promising biocatalyst for the production of chiral α-hydroxyketones. WT EcPDH E1 shows a 180–250-fold higher catalytic efficiency towards 2-oxobutyrate or pyruvate, respectively, in comparison to engineered transketolase variants from Geobacillus stearothermophilus (TKGST). Its broad active site cleft allows for the efficient conversion of both (R)- and (S)-configured α-hydroxyaldehydes, next to linear and branched aliphatic aldehydes as acceptor substrates under kinetically controlled conditions. The alternate, thermodynamically controlled self-reaction of aliphatic aldehydes was shown to be limited to low levels of conversion, which we propose to be due to their large hydration constants. Additionally, the thermodynamically controlled approach was demonstrated to suffer from a loss of stereoselectivity, which makes it unfeasible for aliphatic substrates. Keywords: Thiamine diphosphate; transketolase; C-C bond formation; kinetic control; acyloins 1.
    [Show full text]
  • Linking Vitamin B1 with Cancer Cell Metabolism Jason a Zastre*, Rebecca L Sweet, Bradley S Hanberry and Star Ye
    Zastre et al. Cancer & Metabolism 2013, 1:16 http://www.cancerandmetabolism.com/content/1/1/16 Cancer & Metabolism REVIEW Open Access Linking vitamin B1 with cancer cell metabolism Jason A Zastre*, Rebecca L Sweet, Bradley S Hanberry and Star Ye Abstract The resurgence of interest in cancer metabolism has linked alterations in the regulation and exploitation of metabolic pathways with an anabolic phenotype that increases biomass production for the replication of new daughter cells. To support the increase in the metabolic rate of cancer cells, a coordinated increase in the supply of nutrients, such as glucose and micronutrients functioning as enzyme cofactors is required. The majority of co- enzymes are water-soluble vitamins such as niacin, folic acid, pantothenic acid, pyridoxine, biotin, riboflavin and thiamine (Vitamin B1). Continuous dietary intake of these micronutrients is essential for maintaining normal health. How cancer cells adaptively regulate cellular homeostasis of cofactors and how they can regulate expression and function of metabolic enzymes in cancer is underappreciated. Exploitation of cofactor-dependent metabolic pathways with the advent of anti-folates highlights the potential vulnerabilities and importance of vitamins in cancer biology. Vitamin supplementation products are easily accessible and patients often perceive them as safe and beneficial without full knowledge of their effects. Thus, understanding the significance of enzyme cofactors in cancer cell metabolism will provide for important dietary strategies and new molecular targets to reduce disease progression. Recent studies have demonstrated the significance of thiamine-dependent enzymes in cancer cell metabolism. Therefore, this review discusses the current knowledge in the alterations in thiamine availability, homeostasis, and exploitation of thiamine-dependent pathways by cancer cells.
    [Show full text]
  • Adenosyl Radical: Reagent and Catalyst in Enzyme Reactions E
    DOI: 10.1002/cbic.200900777 Adenosyl Radical: Reagent and Catalyst in Enzyme Reactions E. Neil G. Marsh,*[a] Dustin P. Patterson,[a] and Lei Li*[b] 604 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim ChemBioChem 2010, 11, 604 – 621 Adenosine is undoubtedly an ancient biological molecule that confined to a rather narrow repertoire of rearrangement reac- is a component of many enzyme cofactors: ATP, FADH, tions involving 1,2-hydrogen atom migrations; nevertheless, NAD(P)H, and coenzyme A, to name but a few, and, of course, mechanistic insights gained from studying these enzymes have of RNA. Here we present an overview of the role of adenosine proved extremely valuable in understanding how enzymes in its most reactive form: as an organic radical formed either generate and control highly reactive free radical intermediates. by homolytic cleavage of adenosylcobalamin (coenzyme B12, In contrast, there has been a recent explosion in the number AdoCbl) or by single-electron reduction of S-adenosylmethio- of radical-AdoMet enzymes discovered that catalyze a remarka- nine (AdoMet) complexed to an iron–sulfur cluster. Although bly wide range of chemically challenging reactions; here there many of the enzymes we discuss are newly discovered, adeno- is much still to learn about their mechanisms. Although all the sine’s role as a radical cofactor most likely arose very early in radical-AdoMet enzymes so far characterized come from anae- evolution, before the advent of photosynthesis and the pro- robically growing microbes and are very oxygen sensitive, duction of molecular oxygen, which rapidly inactivates many there is tantalizing evidence that some of these enzymes radical enzymes.
    [Show full text]
  • ITD 5135 Cellular and Systems Processes
    Biology of Cells and Tissues Vadivel Ganapathy, Ph.D. 5B106 [email protected] Fructose and Galactose metabolism Fructose Fructose is important in humans since it represents 50% of the carbohydrate in sucrose. 1 Fructose --- Fructose-1-phosphate ATP 2 Fructose-1-phosphate --- Dihydroxyacetone phosphate + Glyceraldehyde 3 Glyceraldehyde --- Glyceraldehyde-3-phosphate Reaction #1: Fructokinase Reaction #2: Fructose-1-phosphate aldolase Reaction #3: Triose kinase Dihydroxyacetone phosphate and glyceraldehyde-3-phosphate are intermediates in glycolysis. Galactose Galactose is a component of lactose (milk sugar). 1 Galactose --- Galactose-1-phosphate 2 Galactose-1-phosphate + UDP-glucose ---Glucose-1-phosphate + UDG-galactose 3 UDP-galactose --- UDP-glucose 4 Glucose-1-phosphate --- Glucose-6-phosphate (an intermediate in glycolysis) Reaction #1: Galactokinase Reaction #2: Galactose-1-phosphate uridyl transferase Reaction #3: UDP-galactose 4-epimerase Reaction #4: Phosphoglucomutase Hereditary fructose intolerance 1. Genetic disease associated with a deficiency in liver fructose 1-phosphate aldolase. 2. Ingestion of fructose results in the accumulation of fructose 1-phosphate. 3. This depletes the Pi and ATP in the liver. 4. Fructose 1-phosphate stimulates glucokinase in liver and pancreatic β cells by removing the inhibitory protein. This causes increased uptake of glucose by these tissues and also increased insulin secretion by β cells. The result is hypoglycemia. 5. The disease is also associated with liver disease (jaundice) and renal tubular damage (Fanconi syndrome). 6. Decreased Pi levels leads to increased breakdown of adenine nucleotides (AMP, ADP), causing hyperuricemia (gout). 7. No cataract (Fructose, being a ketose, is not a substrate for aldose reductase). 8. Treated by restricting dietary intake of fructose, sucrose, fruit juices and honey.
    [Show full text]
  • Food Supplements: Permitted Vitamins and Minerals
    Food Supplements List of Vitamins and Minerals which may be used in the manufacture of food supplements in the EU Digital ISBN 978 0 7504 7646 1 © Crown copyright 2012 WG15822 Important note This document was correct at the time of publishing. The lists of vitamins and minerals permitted for use in food supplements is subject to change. Please ensure you check the European Commission’s website for any amendments to the list (Click here) Vitamins and minerals which may be used in the manufacture of food supplements as permitted by Directive 2002/46/EC relating to food supplements1 Vitamins Unit of Minerals Unit of measurement measurement Vitamin A μg RE Calcium mg Vitamin D μg Magnesium mg Vitamin E mg α-TE Iron mg Vitamin K μg Copper μg Vitamin B1 mg Iodine μg Vitamin B2 mg Zinc mg Niacin mg NE Manganese mg Pantothenic acid mg Sodium mg Vitamin B6 mg Potassium mg Folic acid2 μg Selenium μg Vitamin B12 μg Chromium μg Biotin μg Molybdenum μg Vitamin C mg Fluoride mg Chloride mg Phosphorus mg Boron mg Silicon mg 1 As amended by Regulation (EC) No. 1137/2008 (OJ L311, 21.11.2008, p.1; Regulation (EC) No. 1170/2009 (OJ L314, 1.12.2009, p.36); and Regulation (EC) No. 1161/2011 (OJ L296, 15.11.2011, p.29) 2 Folic acid is the term included in Annex I of Commission Directive 2008/100/EC of 28 October 2008 amending Council Directive 90/496/EEC on nutrition labelling for foodstuffs as regards recommended daily allowances, energy conversion factors and definitions for nutrition labelling purposes and covers all forms of folates." Vitamins VITAMIN
    [Show full text]
  • Thiamine Pyrophosphate
    CO-ENZYMES Coenzymes are organic non-protein molecules that bind with the protein molecule (apoenzyme) to form the active enzyme (holoenzyme). » Coenzymes are small molecules. » They cannot catalyze a reaction by themselves but they can help enzymes to do so. Example: Thiamine pyrophosphate, FAD, pantothenic acid etc. Salient features of coenzyme: Coenzymes are heat stable. They are low-molecular weight substances. The coenzymes combine loosely with the enzyme molecules and so, the coenzyme can be separated easily by dialysis. When the reaction is completed, the coenzyme is released from the apo-enzyme, and goes to some other reaction site. Thiamine pyrophosphate: Thiamine pyrophosphate (TPP), or thiamine diphosphate (ThDP), is a thiamine derivative, is also known as vitamin B1. Biological Function of Thiamine pyrophosphate: It maintains: The normal function of the heart; Normal carbohydrate and energy-yielding metabolism; The normal function of the nervous system; Normal neurological development and function; Normal psychological functions. Flavin Coenzymes: Flavin mono nucleotide (FMN) Flavin adenine di nucleotide (FMD) Flavin is the common name for a group of organic compounds based on pteridine,. The biochemical source is the riboflavin. It is commonly know as Vitamin B2. The flavin often attached with an adenosine diphosphate to form flavin adenine dinucleotide (FAD),and, in other circumstances, is found as flavin mononucleotide (FMN). Biological Functions and Importance: Normal energy-yielding metabolism; Normal metabolism of iron in the body; The maintenance of normal skin and mucous membranes; The maintenance of normal red blood cells; The maintenance of normal vision; The maintenance of the normal function of the nervous system. TH4 or Tetrahydrofolic acid: Tetrahydrofolic acid, or tetrahydrofolate, is a folic acid derivative.
    [Show full text]