DOCSLIB.ORG

Chapter 1 Introduction and Main Aims

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Chapter 1 Introduction and Main Aims Chapter 1 Introduction and main aims CONTENTS. 1.1 – Branched chain aminotransferase.................................................................... 2 1.2 – hBCAT enzyme kinetics. ................................................................................... 4 1.3 – The structure of the hBCAT proteins. .............................................................. 6 1.4 – Human branched-chain amino acid metabolism. .......................................... 10 1.5 – Redox regulation of hBCAT and relation to other redox proteins. ............... 15 1.6 – hBCAT distribution. ......................................................................................... 19 1.7 – BCAT and the glutamate-glutamine cycle. ..................................................... 21 1.8 – hBCAT and the BCAAs in the brain. ............................................................... 25 1.8.1 – Maple syrup urine disease. .......................................................................... 25 1.8.2 – Excitotoxicity pathway. ................................................................................ 27 1.9 – Alzheimer’s disease. ........................................................................................ 31 1.9.1 – Amyloid pathology. ...................................................................................... 32 1.9.2 – Tau pathology. ............................................................................................. 33 1.9.3 – Protein synthesis and autophagy. ................................................................ 35 1.9.4 – Protein misfolding and redox pathology. ...................................................... 37 1.9.5 – The blood-brain barrier. ............................................................................... 38 1.10 – Aims and objectives. ..................................................................................... 45 1 Chapter 1 – Introduction and main aims. Forshaw, T. E. (2016) 1.1 – Branched chain aminotransferase. Branched chain aminotransferase (BCAT) [E. C. 2.6.1.42] is a highly conserved enzyme essential for mammalian branched chain L-amino acid (BCAA) and branched chain keto acid (BCKA) metabolism (Bledsoe et al., 1997; Ichihara & Koyama, 1966; Schuldiner et al., 1996; Suryawan et al., 1998). The most described function of the BCAT enzymes is to catalyse the reversible transamination of the BCAAs (L-leucine, L-valine and L- isoleucine) and α-ketoglutarate (KG), to generate L-glutamate and the respective BCKAs (α-ketoisocaproate (KIC), α-ketoisovalerate (KIV), and α-keto-β-methylvalerate (KMV) (Scheme 1.1). Rat in vivo studies utilising 15N-labelled L-leucine have determined that the preferred direction of transamination is towards L-glutamate production, although labelled L-isoleucine and L-valine were also detected (Kanamori et al., 1998; Sakai et al., 2004). Specifically, in rat neurons it has been observed that the BCAT enzymes are involved in the de novo synthesis of approximately 30% of brain glutamate (LaNoue et al., 2001). Scheme 1.1 – Transamination catalysed by BCAT. Human BCAT (hBCAT) exists as two isozymes, the cytosolic (hBCATc) and the mitochondrial (hBCATm), which show distinct cellular localisation (Hutson et al., 1988). Human BCATc and hBCATm have a molecular mass of 44.3 kDa and 41.7 kDa, respectively, and their primary amino acid sequence has 395 and 365 amino acids, respectively. These isozymes share 58% amino acid homology, with the greatest homology in the active sites (Davoodi et al., 1998). Both of the full length enzymes have been purified, first from rat tissue (Hall et al., 1993), and later the human protein from cloned genes overexpressed in E. coli (Davoodi et al., 1998). This has allowed for detailed kinetic and redox characterisation, as well as solving of the crystal structures (Conway et al., 2002; Conway et al., 2008; Goto et al., 2005; Yennawar et al., 2001). 2 Chapter 1 – Introduction and main aims. Forshaw, T. E. (2016) As with all aminotransferases, hBCAT uses a pyridoxal phosphate (PLP) co-factor which is bound to an active site L-lysine residue. The PLP-dependent enzyme family is divided into five different ‘fold types’ by the specific orientation of PLP within the active site (Reviewed by Eliot & Kirsch, 2004). While most mammalian aminotransferases belong to fold type I, hBCAT is the only mammalian type IV aminotransferase (Yennawar et al., 2001; Yennawar et al., 2002). The other fold type IV enzymes are bacterial D-amino acid aminotransferases (Martínez del Pozo et al., 1989); differing significantly from the type I and II in that the active site has a mirror image orientation (Yennawar et al., 2001). In fold type IV enzymes, the active site L-lysine residue is bound to PLP on the re face of the chiral centre, exposing the si face to solvent, while the opposite is true for type I aminotransferases (Sugio et al., 1995). This suggests that hBCAT may have a different role in mammals from that of other aminotransferases. The genes for hBCATc and hBCATm are BCAT1 and BCAT2, respectively. Both genes can be transcribed by activating transcription factor 4 (ATF4) and hBCATm alone by C/EBP homologous protein (CHOP), in response to cellular stresses such as starvation, misfolded proteins, and oxidative stress (Harding et al., 2003; Han et al., 2013). Additionally, the BCAT1 gene may be promoted by c-myc, which is involved in cell cycle progression and apoptosis (Ben-Yosef et al., 1998) and the gene has been described as an oncogene (Zhou et al., 2013; Tönjes et al., 2013). There are five variants of BCAT1 mRNA, however, four of these have only been observed in cDNA arrays and only the longest variant is observed as hBCATc protein (Ota et al., 2004; Bechtel et al., 2007). Likewise, the longest transcript of the BCAT2 gene translates to the most widely observed hBCATm protein (Than et al., 2001). Unlike hBCATc, the BCAT2 gene has been obsevered to be transcribed by Kruppel-Like factor 15 (Klf15), a glucocorticoid receptor target (Kuo et al., 2013; Shimizu et al., 2011). There are two additional splice variants of BCAT2 (Than et al., 2001; Lin et al., 2001). The first, placental protein 18b (PP18b), is weakly expressed in many tissues, although its function is not clearly understood (Than et al., 2001). The variant protein has a molecular weight 3 Chapter 1 – Introduction and main aims. Forshaw, T. E. (2016) approximately 8 kDa lighter than hBCATm and lacks the N-terminal mitochondrial targeting sequence, resulting in cytoplasmic localisation (Than et al., 2001). The second transcript, termed P3, was identified as an inhibitor of thyroid hormone receptor (TR) transcriptional activity (Lin et al., 2001). This varient localises to both the mitochondria and nucleus of cells, acting both as a TR antagonist and as an inhibitor of TR binding to DNA. This suggests that hBCATm may control expression of other proteins, although P3 is currently the only isoform published as demonstrating this activity. 1.2 – hBCAT enzyme kinetics. Characterisation of hBCAT has demonstrated that the enzymes both follow the common aminotransferase ‘ping pong bi bi’ mechanism for multi-substrate enzymes, as described by Cleland (1963). For this it is a requirement that PLP is bound as a Schiff base to the Ɛ-amine of active site lysine (Lys202 for hBCATm and Lys222 for hBCATc) to form an enzyme-cofactor complex (E-PLP). The first step in catalysis is the modification of the complex by transfer of an amine group from a substrate L-amino acid to PLP, forming pyridoxamine phosphate (PMP) and releasing an α-keto acid as a first product (Figure 1.1). In the next step, a substrate α-keto acid abstracts the amino group from PMP in a reaction catalysed by the protein, restoring the molecule to the native PLP form and releasing an amino acid product (Figure 1.1). Through both steps the cofactor will disassociate and form external aldimine and ketimine intermediates with the substrate, before reassociation as an E-PLP or enzyme-PMP (E-PMP) complex (Yennawar et al., 2002). In addition to the earlier described substrates, the straight chain analogues of L- valine (norvaline) and L-leucine (norleucine) and the α-keto acid conjugate of methionine (α-keto-γ-methiobutyrate) are substrates for hBCAT. However, neither of D-isoleucine, the aromatic essential L-amino acids L-alanine or L-aspartate were active substrates (Davoodi et al., 1998). Kinetic studies of the hBCAT enzymes have determined that the first step of transamination is the slower rate determining step, while the second step has 4 Chapter 1 – Introduction and main a ims . Forshaw, T. (2016) E. Figure 1.1 – Ping-pong kinetics of the BCAT enzymes. The timeline illustrates the course of transamination from amino acid to α-keto acid. Starting from the left side, the amine group from an amino acid is transferred to enzyme-PLP complex to form PMP and an α-keto acid. The α- keto acid is then released and an enzyme-PMP complex is formed. An α-keto acid may then react with the complex and abstract the amino group from PMP, resulting in release of amino acid and restoration of the enzyme-PLP complex. Abbreviations: PLP – co-factor. PMP – amine modified co-factor. E-PLP/PMP – complex of enzyme and co-factor. BCAA – branched-chain amino acid. Glu – L-glutamate. 5 Chapter 1 – Introduction and main aims. Forshaw, T. E. (2016) a turnover rate approximately double that of the first (Table 1.1). Further characterisation by Yennawar et al. (2006) determined that the equilibrium constant (Keq) for each of the
Load more

Recommended publications
  • Como As Enzimas Agem?
    O que são enzimas? Catalizadores biológicos - Aceleram reações químicas específicas sem a formação de produtos colaterais PRODUTO SUBSTRATO COMPLEXO SITIO ATIVO ENZIMA SUBSTRATO Características das enzimas 1 - Grande maioria das enzimas são proteínas (algumas moléculas de RNA tem atividade catalítica) 2 - Funcionam em soluções aquosas diluídas, em condições muito suaves de temperatura e pH (mM, pH neutro, 25 a 37oC) Pepsina estômago – pH 2 Enzimas de organismos hipertermófilos (crescem em ambientes quentes) atuam a 95oC 3 - Apresentam alto grau de especificidade por seus reagentes (substratos) Molécula que se liga ao sítio ativo Região da enzima e que vai sofrer onde ocorre a a ação da reação = sítio ativo enzima = substrato 4 - Peso molecular: varia de 12.000 à 1 milhão daltons (Da), são portanto muito grandes quando comparadas ao substrato. 5 - A atividade catalítica das Enzimas depende da integridade de sua conformação protéica nativa – local de atividade catalítica (sitio ativo) Sítio ativo e toda a molécula proporciona um ambiente adequado para ocorrer a reação química desejada sobre o substrato A atividade de algumas enzimas podem depender de outros componentes não proteicos Enzima ativa = Holoenzimas Parte protéica das enzimas + cofator Apoenzima ou apoproteína •Íon inorgânico •Molécula complexa (coenzima) Covalentemente ligados à apoenzima GRUPO PROSTÉTICO COFATORES Elemento com ação complementar ao sitio ativo as enzimas que auxiliam na formação de um ambiente ideal para ocorrer a reação química ou participam diretamente dela
    [Show full text]
  • University Microfilms
    INFORMATION TO USERS This dissertation was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted. The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting thru an image and duplicating adjacent pages to insure you complete continuity. 2. When an image on the film is obliterated with a large round black mark, it is an indication that the photographer suspected that the copy may have moved during exposure and thus cause a blurred image. You will find a good image of the page in the adjacent frame. 3. Wher, a map, drawing or chart, etc., was part of the material being photographed the photographer followed a definite method in "sectioning" the material. It is customary to begin photoing at the upper left hand corner of a large sheet and to continue photoing from left to right in equal sections with a small overlap. If necessary, sectioning is continued again - beginning below the first row and continuing on until complete. 4. The majority of users indicate that the textual content is of greatest value, however, a somewhat higher quality reproduction could be made from "photographs" if essential to the understanding of the dissertation.
    [Show full text]
  • Optimizing Cellular Metabolism to Improve Chronic Skin Wound Healing
    Optimizing Cellular Metabolism to Improve Chronic Skin Wound Healing James J. Slade Honors Thesis Luis Felipe Ramirez Biomedical Engineering Rutgers University, New Brunswick Under the direction of Dr. Francois Berthiaume and Dr. Gabriel Yarmush Abstract—Despite significant advances, chronic skin wounds Wound healing is a complex process with four identifiable remain a large problem both in terms of morbidity and cost. It stages: hemostasis, inflammation, proliferation, and remodel- is estimated that in the United States, this problem afflicts 6.5 ing [6]. Hemostasis involves the formation of a blood clot that million people a year and costs more than 30 billion dollars for di- abetic foot ulcers alone [4,11]. Currently approved treatments are stops the loss of blood at the site of injury [6]. Growth factors often ineffective. This thesis seeks to leverage the large amount of released by activated platelets during the hemostasis stage information that has accumulated about metabolism in the hu- recruit immune cells such as neutrophils and macrophages [6]. man body, and to mine that information with computational mod- The infiltration of the injured tissue with these immune cells eling. It seeks to uncover whether metabolites commonly available leads to the inflammatory phase [6]. The role played by inflam- in the human body can be used to bolster the metabolism of wounded cells such as keratinocytes (the cells that form the mation is classified as both positive and negative [5]. On the epidermis), and therefore improve the natural process of wound one hand the inflammatory response clears the wound site of healing. This would offer treatment options with fewer side effects pathogens and dead cells, on the other hand the inflammatory than what is currently offered to improve wound healing.
    [Show full text]
  • The Effect of Osmotic Shock on Release of Bacterial Proteins and on Active Transport
    The Effect of Osmotic Shock on Release of Bacterial Proteins and on Active Transport LEON A. HEPPEL From the Department of Biochemistry and Molecular Biology, Corncll University, Ithaca, New York 14850 ABSTRACT Osmotic shock is a procedure in which Gram-negative bacteria are treated as follows. First they are suspended in 0.5 ~t sucrose containing ethylenediaminetetraacetate. After removal of the sucrose by centrifugation, the pellet of ceils is rapidly dispersed in cold, very dilute, MgC12. This causes the selective release of a group of hydrolytic enzymes. In addition, there is selective release of certain binding proteins. So far, binding proteins for D-galac- tose, L-leucine, and inorganic sulfate have been discovered and purified. The binding proteins form a reversible complex with the substrate but catalyze no chemical change, and no enzymatic activities have been detected. Various lines of evidence suggest that the binding proteins may play a role in active transport: (a) osmotic shock causes a large drop in transport activity associated with the release of binding protein; (b) transport-negative mutants have been found which lack the corresponding binding protein; (¢) the affinity constants for binding and transport are similar; and (d) repression of active transport of leucine was accompanied by loss of binding protein. The binding proteins and hydrolytic enzymes released by shock appear to be located in the cell envelope. Glucose 6-phosphate acts as an inducer for its own transport system when supplied exogenously, but not when generated endogenously from glucose. In recent years, investigators have directed attention to a group of degradative enzymes and other proteins in Escherichia cdi and related Gram-negative organisms which are not bound to isolated cell wails or membranes; yet it is believed that they are confined to a surface compartment rather than existing free in the cytoplasm.
    [Show full text]
  • Radhakrishnan, Iii 4
    NATURE OF THE GENETIC BLOCKS IN THE ISOLEUCINE-VALINE MUTANTS OF SALMONELLA R. P. WAGNER AND ARLOA BERGQUIST The Genetics Laboratory of the Department of Zoology, The Uniuersity of Texas, Austin, Texas Received April 26, 1960 HE metabolic pathways leading to the biosynthesis of isoleucine and valine are now sufficiently well understood, as a result of the work of a number of investigators ( STRASSMAN,THOMAS and WEINHOUSE1955; STRASSMAN,THOMAS, LOCKEand WEINHOUSE1956; STRASSMAN,SHATTON, CORSEY and WEINHOUSE 1958; UMBARGER1958a,b; ADELBERG1955; WAGNER,RADHAKRISHNAN and SNELL1958; RADHAKRISHNAN,WAGNER and SNELL1960; and RADHAKRISHNAN and SNELL1960) to make it possible to investigate the nature of the genetic blocks in mutant organisms requiring isoleucine and valine. This communication describes the results of the investigation of a series of mutants of Salmonella typhimurium originally isolated in the laboratory of DR. M. DEMEREC,The Carnegie Institute of Washington, Cold Spring Harbor, New York. It is limited to the purely biochemical aspects of these mutants, but is ,preceded by a com- munication from GLANVILLEand DEMEREC1960, which describes the linkage studies made with these mutants, and correlates the genetic with the biochemical 3ata. The biosynthesis of isoleucine and valine is believed to occur as shown in Figure 1. In the work to be described here only the steps proceeding from the 3-keto acids, a-acetolactic acid and a-aceto-P-hydroxybutyricacid, have been :onsidered in detail. The following abbreviations are used in Figure I and in mbsequent parts of this communication: AHB = a-aceto-a-hydroxybutyric acid; CHa C Ha CHa CHa I 1 I I c*o CHa-C-OH CHfC-OH CHI-C-H 1 I TPNH 1 I c.0 ~ *Valine I COOH COOH I COOH I COOH (PYRUVIC ACID) (ALI I (HKVI I (DHV) I I I I I I I I + Pyruvic Acid Step1 StepII Stepm Step H 4 I I I I cn3 CH, I CH3 I I I I I CHZ C=O I CH~CH~C-OH Threonine-GO I ~CH3CH2-~-OH-C=0I+! I I I I COOH COOH COOH COOH COOH (U-kmtobutyric acid1 (AH01 (HKII (DUI) (KI) FIGURE1 .-The biosynthetic pathway leading to isoleucine and valine.
    [Show full text]
  • Regulation of the Biosynthesis of the Branched-Chain Amino Acids
    Regulation of the Biosynthesis of the Branched-Chain Amino Acids H. E. UMBARGER Department of Biological Science Purdue University Lafayette, Indiana I. Historical Introduction 57 II. Regulation of Metabolic Flow by End-Product Inhibition . 58 A. Inhibition of Threonine Deaminase 59 B. Inhibition of Acetohydroxy Acid Synthetase 64 C. Inhibition of α-Isopropylmalate Synthetase 67 III. Control of Enzyme Level in the Pathways to the Branched-Chain Amino Acids 68 A. Repression of the Leucine Biosynthetic Enzymes 68 B. Repression of the Isoleucine and Valine Biosynthetic Enzymes . 70 IV. The Inhibition of Growth of Eschenchia coli Strain K12 by Valine 73 Note Added in Proof 74 References 75 I. Historical Introduction For a long time the branched-chain amino acids have been considered under a common heading in biochemistry textbooks. The basis for this grouping was solely their structural relationship since, before the advent of isotopie tracer techniques and mutant methodology, so little was known of their catabolism and nothing was known of their biosynthesis. Indeed, on the basis of their catabolism, they might have been considered separately for studies with the diabetic dog revealed that leucine was a "ketogenic" amino acid, valine was "glycogenic" whereas isoleucine was both. One of the earliest rational reasons for suspecting that they might be metabolically related was an antagonism observed by Gladstone (21) in 1939. He noted that the addition of any one of the three branched- chain amino acids to an otherwise sufficient medium prevented the growth of the anthrax bacillus. The three amino acids added together, however, were stimulatory. Gladstone suggested that each of the amino acids might have interfered with either the utilization or the formation of the other two.
    [Show full text]
  • The Whitefly Bacterial Endosymbiont Is a Minimal Amino Acid Factory with Unusual Energetics
    1bioRxiv preprint doi: https://doi.org/10.1101/043349; this version posted March 11, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Nature lessons: the whitefly bacterial endosymbiont is a minimal amino acid factory 2 with unusual energetics 3 4 Jorge Calle-Espinosa1, Miguel Ponce-de-Leon1, Diego Santos-Garcia2,3, Francisco J. Silva2,4, 5 Francisco Montero1* & Juli Peretó2,5* 6 *Corresponding authors: Francisco Montero [email protected] - Juli Peretó 7 [email protected] 8 1 Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, 9 Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain. 10 2 Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, C/José 11 Beltrán 2, Paterna 46980, Spain. 12 3 Present address: Department of Entomology, The Hebrew University of Jerusalem, Israel. 13 4 Departament de Genètica, Universitat de València. 14 5 Departament de Bioquímica i Biologia Molecular, Universitat de València. 15 16 Abstract 17 18 Bacterial lineages that establish obligate symbiotic associations with insect hosts are 19 known to possess highly reduced genomes with streamlined metabolic functions that are 20 commonly focused on amino acid and vitamin synthesis. We constructed a genome-scale 21 metabolic model of the whitefly bacterial endosymbiont Candidatus Portiera aleyrodidarum 22 to study the energy production capabilities using stoichiometric analysis. Strikingly, the 23 results suggest that the energetic metabolism of the bacterial endosymbiont relies on the use 24 of pathways related to the synthesis of amino acids and carotenoids.
    [Show full text]
  • O O2 Enzymes Available from Sigma Enzymes Available from Sigma
    COO 2.7.1.15 Ribokinase OXIDOREDUCTASES CONH2 COO 2.7.1.16 Ribulokinase 1.1.1.1 Alcohol dehydrogenase BLOOD GROUP + O O + O O 1.1.1.3 Homoserine dehydrogenase HYALURONIC ACID DERMATAN ALGINATES O-ANTIGENS STARCH GLYCOGEN CH COO N COO 2.7.1.17 Xylulokinase P GLYCOPROTEINS SUBSTANCES 2 OH N + COO 1.1.1.8 Glycerol-3-phosphate dehydrogenase Ribose -O - P - O - P - O- Adenosine(P) Ribose - O - P - O - P - O -Adenosine NICOTINATE 2.7.1.19 Phosphoribulokinase GANGLIOSIDES PEPTIDO- CH OH CH OH N 1 + COO 1.1.1.9 D-Xylulose reductase 2 2 NH .2.1 2.7.1.24 Dephospho-CoA kinase O CHITIN CHONDROITIN PECTIN INULIN CELLULOSE O O NH O O O O Ribose- P 2.4 N N RP 1.1.1.10 l-Xylulose reductase MUCINS GLYCAN 6.3.5.1 2.7.7.18 2.7.1.25 Adenylylsulfate kinase CH2OH HO Indoleacetate Indoxyl + 1.1.1.14 l-Iditol dehydrogenase L O O O Desamino-NAD Nicotinate- Quinolinate- A 2.7.1.28 Triokinase O O 1.1.1.132 HO (Auxin) NAD(P) 6.3.1.5 2.4.2.19 1.1.1.19 Glucuronate reductase CHOH - 2.4.1.68 CH3 OH OH OH nucleotide 2.7.1.30 Glycerol kinase Y - COO nucleotide 2.7.1.31 Glycerate kinase 1.1.1.21 Aldehyde reductase AcNH CHOH COO 6.3.2.7-10 2.4.1.69 O 1.2.3.7 2.4.2.19 R OPPT OH OH + 1.1.1.22 UDPglucose dehydrogenase 2.4.99.7 HO O OPPU HO 2.7.1.32 Choline kinase S CH2OH 6.3.2.13 OH OPPU CH HO CH2CH(NH3)COO HO CH CH NH HO CH2CH2NHCOCH3 CH O CH CH NHCOCH COO 1.1.1.23 Histidinol dehydrogenase OPC 2.4.1.17 3 2.4.1.29 CH CHO 2 2 2 3 2 2 3 O 2.7.1.33 Pantothenate kinase CH3CH NHAC OH OH OH LACTOSE 2 COO 1.1.1.25 Shikimate dehydrogenase A HO HO OPPG CH OH 2.7.1.34 Pantetheine kinase UDP- TDP-Rhamnose 2 NH NH NH NH N M 2.7.1.36 Mevalonate kinase 1.1.1.27 Lactate dehydrogenase HO COO- GDP- 2.4.1.21 O NH NH 4.1.1.28 2.3.1.5 2.1.1.4 1.1.1.29 Glycerate dehydrogenase C UDP-N-Ac-Muramate Iduronate OH 2.4.1.1 2.4.1.11 HO 5-Hydroxy- 5-Hydroxytryptamine N-Acetyl-serotonin N-Acetyl-5-O-methyl-serotonin Quinolinate 2.7.1.39 Homoserine kinase Mannuronate CH3 etc.
    [Show full text]
  • Regulation of Leucine Catabolism by Caloric Sources. Role of Glucose and Lipid in Nitrogen Sparing During Nitrogen Deprivation
    Regulation of leucine catabolism by caloric sources. Role of glucose and lipid in nitrogen sparing during nitrogen deprivation. J A Vazquez, … , H S Paul, S A Adibi J Clin Invest. 1988;82(5):1606-1613. https://doi.org/10.1172/JCI113772. Research Article Previously we showed that hypocaloric amounts of glucose reduce leucine catabolism while an isocaloric amount of fat does not (1985. J. Clin. Invest. 76:737.). This study was designed to investigate whether the same difference exists when the entire caloric need is provided either as glucose or lipid. Rats were maintained for 3 d on total parenteral nutrition (350 cal/kg per d), after which the infusion of amino acids was discontinued and rats received the same amount of calories entirely as glucose or lipid for three more days. A third group of rats was infused with saline for 3 d. In comparison to glucose, lipid infusion resulted in higher urinary nitrogen excretion (55 +/- 3 vs. 37 +/- 2 mg N/24 h, P less than 0.05), muscle concentrations of tyrosine (95 +/- 8 vs. 42 +/- 8 microM, P less than 0.01), and leucine (168 +/- 19 vs. 84 +/- 16 microM, P less than 0.01), activity of BCKA dehydrogenase in muscle (2.2 +/- 0.2 vs. 1.4 +/- 0.04 nmol/mg protein per 30 min, P less than 0.05), and whole body rate of leucine oxidation (3.3 +/- 0.5 vs. 1.4 +/- 0.2 mumol/100 g per h, P less than 0.05). However, all these parameters were significantly lower in lipid-infused than starved rats.
    [Show full text]
  • Method for Producing L-Leucine Verfahren Zur Herstellung Von L-Leucin Procédé De Préparation De L-Leucine
    Europäisches Patentamt *EP000913466B1* (19) European Patent Office Office européen des brevets (11) EP 0 913 466 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.7: C12N 1/20, C12P 13/06 of the grant of the patent: // (C12N1/20, C12R1:19) 07.04.2004 Bulletin 2004/15 (21) Application number: 98120261.7 (22) Date of filing: 26.10.1998 (54) Method for producing L-leucine Verfahren zur Herstellung von L-Leucin Procédé de préparation de L-leucine (84) Designated Contracting States: • Arkadievich, Livshits Vitaly (VNIIGenetika) DE FR NL SE 113545, Moscow (RU) • Ivanovich, Kozlov Yury (VNIIGenetika) (30) Priority: 29.10.1997 RU 97117875 113545, Moscow (RU) • Georgievich, Debabov Vladimir (VNIIGenetika) (43) Date of publication of application: 113545, Moscow (RU) 06.05.1999 Bulletin 1999/18 (74) Representative: Strehl Schübel-Hopf & Partner (73) Proprietor: Ajinomoto Co., Inc. Maximilianstrasse 54 Tokyo (JP) 80538 München (DE) (72) Inventors: (56) References cited: • Markovich, Gusyatiner Mikhail (VNIIGenetika) EP-A- 0 530 803 EP-A- 0 698 668 113545, Moscow (RU) US-A- 3 970 519 • Grigorievna, Lunts Maria (VNIIGenetika) 113545, Moscow (RU) • CALHOUN D H: "Threonine deaminase from • Valerievna, Ivanovskaya Lirina (VNIIGenetika) Escherichia coli: feedback- hypersensitive 113545, Moscow (RU) enzyme from a genetic regulatory mutant." • Georgievna, Rostova Yulia (VNIIGenetika) JOURNAL OF BACTERIOLOGY, (1976 APR) 126 113545, Moscow (RU) (1) 56-63. , XP002122210 • Aleksandrovna, Bachina Tatiana (VNIIGenetika) 113545, Moscow (RU) Remarks: • Zavenovich, Akhverdyan Valery (VNIIGenetika) The file contains technical information submitted 113545, Moscow (RU) after the application was filed and not included in this • Moiseevich, Khurges Evgeny (VNIIGenetika) specification 113545, Moscow (RU) Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted.
    [Show full text]
  • The Whitefly Bacterial Endosymbiont Is a Minimal Amino Acid Factory
    1bioRxiv preprint doi: https://doi.org/10.1101/043349; this version posted March 11, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Nature lessons: the whitefly bacterial endosymbiont is a minimal amino acid factory 2 with unusual energetics 3 4 Jorge Calle-Espinosa1, Miguel Ponce-de-Leon1, Diego Santos-Garcia2,3, Francisco J. Silva2,4, 5 Francisco Montero1* & Juli Peretó2,5* 6 *Corresponding authors: Francisco Montero [email protected] - Juli Peretó 7 [email protected] 8 1 Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, 9 Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain. 10 2 Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, C/José 11 Beltrán 2, Paterna 46980, Spain. 12 3 Present address: Department of Entomology, The Hebrew University of Jerusalem, Israel. 13 4 Departament de Genètica, Universitat de València. 14 5 Departament de Bioquímica i Biologia Molecular, Universitat de València. 15 16 Abstract 17 18 Bacterial lineages that establish obligate symbiotic associations with insect hosts are 19 known to possess highly reduced genomes with streamlined metabolic functions that are 20 commonly focused on amino acid and vitamin synthesis. We constructed a genome-scale 21 metabolic model of the whitefly bacterial endosymbiont Candidatus Portiera aleyrodidarum 22 to study the energy production capabilities using stoichiometric analysis. Strikingly, the 23 results suggest that the energetic metabolism of the bacterial endosymbiont relies on the use 24 of pathways related to the synthesis of amino acids and carotenoids.
    [Show full text]
  • (12) Patent Application Publication (10) Pub. No.: US 2012/0266329 A1 Mathur Et Al
    US 2012026.6329A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2012/0266329 A1 Mathur et al. (43) Pub. Date: Oct. 18, 2012 (54) NUCLEICACIDS AND PROTEINS AND CI2N 9/10 (2006.01) METHODS FOR MAKING AND USING THEMI CI2N 9/24 (2006.01) CI2N 9/02 (2006.01) (75) Inventors: Eric J. Mathur, Carlsbad, CA CI2N 9/06 (2006.01) (US); Cathy Chang, San Marcos, CI2P 2L/02 (2006.01) CA (US) CI2O I/04 (2006.01) CI2N 9/96 (2006.01) (73) Assignee: BP Corporation North America CI2N 5/82 (2006.01) Inc., Houston, TX (US) CI2N 15/53 (2006.01) CI2N IS/54 (2006.01) CI2N 15/57 2006.O1 (22) Filed: Feb. 20, 2012 CI2N IS/60 308: Related U.S. Application Data EN f :08: (62) Division of application No. 1 1/817,403, filed on May AOIH 5/00 (2006.01) 7, 2008, now Pat. No. 8,119,385, filed as application AOIH 5/10 (2006.01) No. PCT/US2006/007642 on Mar. 3, 2006. C07K I4/00 (2006.01) CI2N IS/II (2006.01) (60) Provisional application No. 60/658,984, filed on Mar. AOIH I/06 (2006.01) 4, 2005. CI2N 15/63 (2006.01) Publication Classification (52) U.S. Cl. ................... 800/293; 435/320.1; 435/252.3: 435/325; 435/254.11: 435/254.2:435/348; (51) Int. Cl. 435/419; 435/195; 435/196; 435/198: 435/233; CI2N 15/52 (2006.01) 435/201:435/232; 435/208; 435/227; 435/193; CI2N 15/85 (2006.01) 435/200; 435/189: 435/191: 435/69.1; 435/34; CI2N 5/86 (2006.01) 435/188:536/23.2; 435/468; 800/298; 800/320; CI2N 15/867 (2006.01) 800/317.2: 800/317.4: 800/320.3: 800/306; CI2N 5/864 (2006.01) 800/312 800/320.2: 800/317.3; 800/322; CI2N 5/8 (2006.01) 800/320.1; 530/350, 536/23.1: 800/278; 800/294 CI2N I/2 (2006.01) CI2N 5/10 (2006.01) (57) ABSTRACT CI2N L/15 (2006.01) CI2N I/19 (2006.01) The invention provides polypeptides, including enzymes, CI2N 9/14 (2006.01) structural proteins and binding proteins, polynucleotides CI2N 9/16 (2006.01) encoding these polypeptides, and methods of making and CI2N 9/20 (2006.01) using these polynucleotides and polypeptides.
    [Show full text]