DOCSLIB.ORG

Protection of the Proteolytic Activity of Crude Papain

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Protection of the Proteolytic Activity of Crude Papain PROTECTION OF THE PROTEOLYTIC ACTIVITY OF CRUDE PAPAIN AND CHEMICAL MODIFICATION OF PAPAIN BY TETRATHIONATE by Guillermo Eleazar Arteaga Mac Kinney Biochemical Engineer Manager in Food Processing, The Institute of Technology and Higher Studies of Monterrey, Mexico, 1984 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (The Department of Food Science) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA JULY 1988 ©Guillermo E. Arteaga Mac Kinney , 1988 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of f-poci ^ciewcg The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 ABSTRACT In the first chapter, sodium tetrathionate (TT), a sulfhydryl blocking agent, is assessed for its ability to protect the proteolytic activity (PA) of papaya latex during air, sun or vacuum drying, and of crude papain during storage. X3 By means of Taguchi's L2? (3 ) fractional factorial design, it was found that the addition of 1% TT significantly increased the retention of PA of papaya latex when it was air dried at a temperature of 55°C. This protection of PA was found to be 23% higher than the one given by the addition of 1% sodium metabisulfite, the compound commonly used in the commercial processing of papaya latex. When drying was carried out either under 27 inches vacuum at 50°C or in the sun, the protective effect of TT on the PA was not significantly different from that of metabisulfite. The PA of crude papain during storage at room temperature was also protected by TT. A loss of 20% of the original PA occurred over a period of 13 wk when crude papain contained 1% TT, compared to a loss of 45% when the crude enzyme preparation contained 1% metabisulfite. In the same chapter five different oxidants for synthesis of TT from thiosulfate are compared, namely: iodine, hydrogen peroxide, ferric chloride, cupric sulfate and sodium vanadate. The results indicated that hydrogen peroxide or sodium vanadate were not only effective in the oxidation but also much less expensive than iodine, which is the most popular oxidant for the synthesis of TT. The results obtained in this chapter warrant the use of TT in the commercial production of commercial papain to prevent the destruction of the enzymes during harvesting, storage, transportation and processing. In the second chapter, chemical modification of pure papain by TT is discussed. Optimization techniques were applied for improving the precision of two methods used in this study: circular dichroism (CD) and proteolytic activity determination. Simplex optimization significantly improved repeatability and signal to noise ratio of the CD scan of papain. A new optimization approach, which was a combination of a central composite rotatable design and simplex optimization, was successfully applied to achieve maximum precision for the proteolytic activity assay of papain using casein as a substrate. This approach may also be applied to other analytical methods to improve the reliability of the experimental data. Influential factors in the inactivation of PA of papain by using TT and reactivation of the inactivated papain by cysteine were carried out using two Taguchi's Lie (21S) fractional factorial designs. The results indicated that when inactivation was carried out at pH 6.8, with a reaction time of 5 min at 22<>C, and a molar ratio of TT to papain of 10, the inactivation reaction was highly reversible upon addition of 20 mM cysteine. -iii- Although some interactions of the factors were significant, 70% reactivation was achieved in most cases. Analysis of UV absorbance, near-UV and far-UV CD spectra indicated that there were no major changes in the spectra in papain upon the chemical modification of the enzyme with TT. Secondary structure computed from far-UV CD spectra also demonstrated no significant changes upon this modification. Sulfhydryl data and pH-fluorescence profiles of the modified papain support the hypothesis that reversible blocking by TT results from binding with the single reactive cysteine residue present in papain. Quenching of the intrinsic fluorescence of papain when the modification was carried out using high molar ratios of TT to papain was suggestive of modification of tryptophan residues in the enzyme during the oxidation reaction with TT. Precipitation or insolubilization of pure papain, and of the proteins of papaya latex and commercial papain was observed upon the chemical modification with TT under certain conditions. Addition of fl-mercaptoethanol and TT at levels of 100 mM and 50 mM, respectively, precipitated 90% of pure papain. Solubility studies together with electrophoretic analysis of the precipitated papain suggested formation of insoluble aggregates due to the insoluble aggregation as a result of inter-molecular disulfide bonds formation. TT was found to be a competitive inhibitor of both reversible and irreversible inhibition of the enzyme action, when -iv- carbobenzoxyglycine p-nitrophenyl ester was used as a substrate. The second order inactivation constant in the absence of substrate was computed to be 16,919 M^sec"1, indicating that the reaction had a high rate. -v- TABLE OP CONTENTS Page ABSTRACT ii TABLE OF CONTENTS vi LIST OF TABLES xii LIST OF FIGURES XV LIST OF APPENDICES xxi ACKNOWLEDGEMENTS XXi i GENERAL INTRODUCTION 1 CHAPTER 1. Protection of the proteolytic activity of papaya latex and crude papain by tetrathionate LITERATURE REVIEW 4 A. Definitions 4 B. Production of papaya latex 5 1. Agronomic factors 5 2. Papaya latex harvesting 6 3. Yields of papaya latex 7 C. Production of crude papain and commercial papain 8 1. Drying 8 2. Refining 10 3. Grades and prices of crude and commercial papain 11 D. Losses of proteolytic activity of papaya latex due to drying and during storage of crude and commercial papain 13 E. Process to improve the stability of crude and commercial papain 15 1. Improvement of tapping and collecting procedures 16 2. The Boudart process 16 3. Addition of reducing agents 17 F. Sodium tetrathionate as a stabilizing agent of sulfhydryl proteases 18 1. Mechanism of reaction 18 2. Reversible inactivation 19 G. Chemical properties of tetrathionate 21 1. Some properties of tetrathionate 22 2. Structure of tetrathionate... 23 3. Uses 23 4. Toxicity 25 -vi- Page H. Preparation of tetrathionate 27 1. Iodine oxidation 29 2. Oxidation with other compounds 31 (a) Oxidation with hydrogen peroxide 31 (b) Oxidation with metal salts 32 (c) Oxidation with vanadate 32 3. Other methods of synthesis of tetrathionate 33 MATERIALS AND METHODS 35 A. Materials 35 B. Rehydration of crude papain 35 C. Drying characteristics of papaya latex 36 D. Determination of influential factors on the losses of proteolytic activity due to drying of papaya latex..36 E. Effect of different types of drying and additives on the losses of proteolytic activity of papaya latex..40 P. Losses of the proteolytic activity of crude papain during storage 41 G. Proteolytic activity assay 41 H. Preparation of sodium tetrathionate 43 1. Iodine oxidation 43 2. Hydrogen peroxide oxidation 43 3. Ferric oxidation 44 4. Cupric oxidation 45 5. Vanadate oxidation 46 I. Determination of purity and yield 46 1. Iodate-iodine titration 46 2. Alkaline cyanolysis 49 3. Melting point determination 50 4. Calculation of purity and yield 50 J. Cost evaluation 51 K. Inactivation/activation efficiency of the synthesized tetrathionates 51 RESULTS AND DISCUSSION 53 A. Drying Rates of papaya latex 53 B. Determination of influential factors on the losses of proteolytic activity due to drying of papaya latex 57 C. Effect of different types of drying and additives on the loss of proteolytic activity of papaya latex 62 D. Effect of additives on loss of the proteolytic activity of crude papain during storage 64 E. Comparison of the different methods to synthesize tetrathionate 66 -vii- Page F. Cost evaluation of the different methods of tetrathionate synthesis 68 G. Melting point determination 74 H. Inactivation/activation efficiency of the synthesized tetrathionates 96 CONCLUSION 98 CHAPTER 2. Chemical modification of papain by tetrathionate LITERATURE REVIEW 100 A. Chemical modification of proteins 100 B. Chemical modification of food related proteins 102 C. Modification of sulfhydryl groups in proteins 103 1, Oxidation 104 (a) Modification by aromatic disulfides 106 (b) Modification by tetrathionate 107 I. Tetrathionate as a stabilizing agent for sulfhydryl proteases 108 II. Tetrathionate as a blocking agent of cysteine residues 108 III. Tetrathionate as a chemical modification agent of cysteine residues 109 (c) Modification by iodobenzoates and mercurials....112 2. Alkylation 113 D. Papain 114 1. Definition and isolation 114 2. Physicochemical properties and structure 115 3. Stability 118 4. Activity 119 E. Chemical modification of papain 119 1. Modification of Cys-25 120 2. Modification of other residues 121 F. Enzyme kinetics 125 1. Reactions rates 125 (a) Zero order reactions 125 (b) First order reactions 126 (c) Second order reactions 126 I. Type I 127 II. Type II 127 III. Type III 127 2. States of an enzymatic reaction 128 (a) The pre-steady state 128 (b) The steady state 130 (c) The nonlinear state 130 -viii- Page 3. Measurement of velocity of enzyme catalyzed reactions 130 (a) Effect of substrate concentration on the initial velocity 131 (b) Determination of Km and Vmax 133 G.
Load more

Recommended publications
  • Risk Assessment Addendum Report – Sodium Thiosulphate (Final) Fraccing Chemicals Assessment Risk Assessment Addendum Report—Sodium Thiosulphate
    Appendix W.3 Fraccing Chemicals Assessment – Risk Assessment Addendum Report – Sodium Thiosulphate (Final) Fraccing Chemicals Assessment Risk Assessment Addendum Report—Sodium Thiosulphate CONFIDENTIAL For QGC LNG May 2011 0123263RP01_Addendum_Final www.erm.com Fraccing Chemicals Assessment Approved by: Wijnand Germs Risk Assessment Addendum Report – Sodium Thiosulphate CONFIDENTIAL Position: Project Manager Signed: QGC LNG Date: 11 May 2011 Approved by: Sophie Wood Position: Partner Signed: 11 May 2011 Date: 11May 2011 Environmental Resources Management Australia Pty Ltd Quality System 0123263RP01_ Addendum Final www.erm.com Quality-ISO-9001-PMS302 This disclaimer, together with any limitations specified in the report, apply to use of this report. This report was prepared in accordance with the contracted scope of services for the specific purpose stated and subject to the applicable cost, time and other constraints. In preparing this report, ERM relied on: (a) client/third party information which was not verified by ERM except to the extent required by the scope of services, and ERM does not accept responsibility for omissions or inaccuracies in the client/third party information; and (b) information taken at or under the particular times and conditions specified, and ERM does not accept responsibility for any subsequent changes. This report has been prepared solely for use by, and is confidential to, the client and ERM accepts no responsibility for its use by other persons. This report is subject to copyright protection and the copyright
    [Show full text]
  • Thiosulfate Degradation During Gold Leaching In
    THIOSULFATE DEGRADATION DURING GOLD LEACHING IN AMMONIACAL THIOSULFATE SOLUTIONS : A FOCUS ON TRITHIONATE By NOELENE AHERN B.Sc, University of Natal, 1994 B.Sc. (Hons), University of Natal, 1995 M.A.Sc, University of Cape Town, 1997 A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Faculty of Graduate Studies (Materials Engineering) The University of British Columbia October 2005 © Noelene Ahern, 2005 ABSTRACT Thiosulfate has shown considerable promise as an alternative to cyanide for gold leaching. However, one of the main limitations of the thiosulfate system is the high consumption of thiosulfate. Besides increasing the cost of the process, the degradation products of thiosulfate have been claimed to passivate gold surfaces and the polythionates often produced are loaded onto resins proposed for gold recovery. The thiosulfate degradation process is not completely understood. Of the degradation products, trithionate is a concern in the resin recovery of gold and is persistent in gold leach solutions. Very little is known about the expected behaviour of trithionate, both with respect to its formation and its interaction with other solution species. The focus of this work was therefore to further the understanding of the behaviour of trithionate in gold leach solutions. Experimental work was carried out to determine the kinetics of trithionate degradation in systems resembling gold leaching solutions, and a kinetic model was derived for trithionate degradation. The rate of degradation of trithionate in aqueous ammoniacal solutions was expressed by Equation 1. 2 + 2 -d[S306 -]/dt = (k3[NH4 ] + k2[NH3] + k,[OHl + k0)[S3O6 T [1] 1 1 1 1 1 where k0 = 0.012 h"\ = 0.74 IvV.h;, k2 = 0.0049 M" .h' , k3 = 0.01 M" .^ .
    [Show full text]
  • Guidance Manual for the Disposal of Chlorinated Water
    GUIDANCE MANUAL FOR THE DISPOSAL OF CHLORINATED WATER Maria W. Tikkanen, Ph.D., East Bay Municipal Utility District, Oakland, CA John H. Schroeter, P.E., East Bay Municipal Utility District, Oakland, CA Lawrence Y.C. Leong, Ph.D., QEP., Kennedy/Jenks Consultants, Irvine, CA Rajagopalan Ganesh, Ph.D., Kennedy/Jenks Consultants, Irvine, CA This document was supplied and copied with the permission of Rajagopalan Ganesh, Ph.D for informational purposes only. We wish to thank Rajagopalan Ganesh, Ph.D for offering this copy, for distribution, of his comprehensive work on dechlorination chemistry and it’s application in treating discharge water. Copied By: (253) 479-7000 or (800) 322-6646 fax (253) 479-7079 or (800) 269-7301 WWW.VITA-D-CHLOR.COM [email protected] THE VITA-D-CHLOR™ COMPANY INTEGRA Chemical Company Ascorbic Acid, NSF and Sodium Ascorbate, NSF 1216 6th Ave N Dechlorination Chemistry for the Environment Kent, WA 98032 GUIDANCE MANUAL FOR THE DISPOSAL OF CHLORINATED WATER Maria W. Tikkanen, Ph.D., East Bay Municipal Utility District, Oakland, CA John H. Schroeter, P.E., East Bay Municipal Utility District, Oakland, CA Lawrence Y.C. Leong, Ph.D., QEP., Kennedy/Jenks Consultants, Irvine, CA Rajagopalan Ganesh, Ph.D., Kennedy/Jenks Consultants, Irvine, CA ABSTRACT Periodically, water utilities discharge finished water containing residual chlorine during emergency and planned activities that may end up in receiving streams. Chlorine is toxic to aquatic life, however, even at concentrations that cannot be detected by field measurements. In addition, the Endangered Species Act may be listing more aquatic species in the near future.
    [Show full text]
  • Biological Evaluation, NPDES General Permit #WAG130000 (Pdf)
    NPDES General Permit WAG130000 Federal Aquaculture Facilities and Aquaculture Facilities Located in Indian Country within the Boundaries of Washington State Biological Evaluation For Endangered Species Act Section 7 Consultation with the National Marine Fisheries Service and the U.S. Fish and Wildlife Service December 23, 2015 Prepared by: Burt Shephard, EPA Region 10 Risk Assessor Andrea LaTier, EPA Region 10 Ecotoxicologist Catherine Gockel, EPA Region 10 NPDES Permit Writer 1 Biological Evaluation - EPA Washington Hatchery NPDES General Permit Table of Contents 1 Introduction ........................................................................................................................................... 4 2 The Action: Reissue NPDES General Permit WAG130000 ..................................................................... 5 2.1 This General Permit: Scope and Eligibility .................................................................................... 5 2.2 Effluent Limitations and Monitoring Requirements ..................................................................... 7 2.3 Quality Assurance and Best Management Practices Plans ......................................................... 15 3 The Action Area: Washington State ..................................................................................................... 19 4 Threatened and Endangered Species .................................................................................................. 21 4.1 Species Descriptions ..................................................................................................................
    [Show full text]
  • University of Nevada, Reno Effects of Reduced Sulfur Species on The
    University of Nevada, Reno Effects of Reduced Sulfur Species on the Recovery of Gold and Silver by Cyanide Leaching A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geo-Engineering by Naci Umut Duru Dr. Carl Nesbitt / Dissertation Advisor August, 2017 Copyright by Naci Umut Duru 2017 All Rights Reserved THE GRADUATE SCHOOL We recommend that the dissertation prepared under our supervision by NACI UMUT DURU Entitled Effects of Reduced Sulfur Species on the Recovery of Gold and Silver by Cyanide Leaching be accepted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Dr. Carl Nesbitt, Advisor Dr. James Hendrix, Committee Member Dr. Thom Seal, Committee Member Dr. George Danko, Committee Member Dr. Cahit Evrensel, Graduate School Representative David W. Zeh, Ph. D., Dean, Graduate School August, 2017 i ABSTRACT Cyanidation circuits that treat sulfidic ores may contain one or more of the following - 2- - reduced sulfur species: sulfide (HS ), polysulfides (Sn ), thiocyanate (SCN ), 2- 2- 2- thiosulfate (S2O3 ), trithionate (S3O6 ), tetrathionate (S4O6 ), pentathionate 2- 2- (S5O6 ), hexathionate (S6O6 ). The actual speciation of the reduced sulfur species in the circuits will primarily depend on the redox potential, pH, cyanide levels and existing sulfur species in recycled process water, as well as the presence of other reactive metal species. Higher polythionates (i.e. tetra-, penta- and hexa-thionate) present in leach solutions react with cyanide ions rapidly and consume the available cyanide causing lower metal recoveries at cyanide leaching plants. However, if higher polythionate ions could be degraded to trithionate, cyanide consumption would be lowered and metal recoveries would be increased.
    [Show full text]
  • Titration Method for Determining Salt Iodate and Salt Iodide Content
    ANNEX 1 Titration method for determining salt iodate and salt iodide content A1.1 Titration method for determining salt iodate content The iodine content of iodated salt samples is measured using the iodo- metric titration method (16,23,37). The method consists of preparing the reagent solutions, which may last for variable periods of time, and then using these reagents in the titration procedure. Usually, salt samples of 10 g each are dissolved in a measured amount of water for the titration analysis. However, in the case of coarse salt and in salt containing impurities, a bigger sample weight of 50 g salt will yield more accurate results. A chemical analyst will be able to advise on the appropriate glassware, preparation of reagents (including adjust- ments to the concentrations of some of the reagents), and the necessary calculations to obtain the correct results. For community or population surveys, 10 g salt samples are sufficient; however, for monitoring the iodine content at the production level, 50 g salt samples are preferred for the titration procedure. A1.1.1 Description of the reaction The reaction mechanism includes two steps: • Liberation of free iodine from salt: The addition of H2S4O liber- ates free iodine from the iodate in the salt sample. Excess KI is added to help solubilise the free iodine, which is quite insoluble in pure water under normal conditions. • Titration of free iodine with thiosulfate: free iodine is consumed by sodium thiosulfate in the titration step. The amount of thiosulfate used is proportional to the amount of free iodine liberated from the salt.
    [Show full text]
  • James Okstate 0664D 13483.Pdf (6.398Mb)
    THE ELUCIDATION AND QUANTIFICATION OF THE DECOMPOSITION PRODUCTS OF SODIUM DITHIONITE AND THE DETECTION OF PEROXIDE VAPORS WITH THIN FILMS By TRAVIS HOUSTON JAMES Bachelor of Science in Chemistry Hillsdale College Hillsdale, MI 2009 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY July, 2014 THE ELUCIDATION AND QUANTIFICATION OF THE DECOMPOSOTION PRODUCTS OF SODIUM DITHIONITE AND THE DETECTION OF PEROXIDE VAPORS WITH THIN FILMS Dissertation Approved: Dr. Nicholas F. Materer Dissertation Advisor Dr. Allen Apblett Dr. Frank Blum Dr. Richard Bunce Dr. Ziad El-Rassi Dr. Tyler Ley ii ACKNOWLEDGEMENTS I would like to thank anyone who, whether I am aware of his or her actions or not, has contributed meaningfully to my life and my efforts. iii Acknowledgements reflect the views of the author and are not endorsed by committee members or Oklahoma State University. Name: TRAVIS HOUSTON JAMES Date of Degree: JULY, 2014 Title of Study: THE ELUCIDATION AND QUANTIFICATION OF THE DECOMPOSOTION PRODUCTS OF SODIUM DITHIONITE AND THE DETECTION OF PEROXIDE VAPORS WITH THIN FILMS Major Field: CHEMISTRY Abstract: Sodium dithionite (Na2S2O4) is an oxidizable sulfur oxyanion often employed as a reducing agent in environmental and synthetic chemistry. When exposed to the atmosphere, dithionite degrades through a series of decomposition reactions to form a 2- number of compounds, with the primary two being bisulfite (HSO3 ) and thiosulfate 2- (S2O3 ). Ten samples of sodium dithionite ranging from brand new to nearly fifty years old were analyzed using ion chromatography; from this, a new quantification method for dithionite and thiosulfate was achieved and statistically validated against the current three iodometric titration method used industrially.
    [Show full text]
  • Aldrich Organometallic, Inorganic, Silanes, Boranes, and Deuterated Compounds
    Aldrich Organometallic, Inorganic, Silanes, Boranes, and Deuterated Compounds Library Listing – 1,521 spectra Subset of Aldrich FT-IR Library related to organometallic, inorganic, boron and deuterium compounds. The Aldrich Material-Specific FT-IR Library collection represents a wide variety of the Aldrich Handbook of Fine Chemicals' most common chemicals divided by similar functional groups. These spectra were assembled from the Aldrich Collection of FT-IR Spectra and the data has been carefully examined and processed by Thermo. The molecular formula, CAS (Chemical Abstracts Services) registry number, when known, and the location number of the printed spectrum in The Aldrich Library of FT-IR Spectra are available. Aldrich Organometallic, Inorganic, Silanes, Boranes, and Deuterated Compounds Index Compound Name Index Compound Name 1066 ((R)-(+)-2,2'- 1062 (1,3- BIS(DIPHENYLPHOSPHINO)-1,1'- BIS(DIPHENYLPHOSPHINO)PROPA BINAPH)(1,5-CYCLOOCTADIENE) NE)DICHLORONICKEL(II) 1068 ((R)-(+)-2,2'- 598 (1,3-DIOXAN-2- BIS(DIPHENYLPHOSPHINO)-1,1'- YLETHYNYL)TRIMETHYLSILANE, BINAPHTHYL)PALLADIUM(II) CH 96% 1067 ((S)-(-)-2,2'- 1063 (1,4- BIS(DIPHENYLPHOSPHINO)-1,1'- BIS(DIPHENYLPHOSPHINO)BUTAN BINAPH)(1,5-CYCLOOCTADIENE) E)(1,5- 1140 (+)-(S)-1-((R)-2- CYCLOOCTADIENE)RHODIUM(I) (DIPHENYLPHOSPHINO)FERROCE TET NYL)ETHYL METHYL ETHER, 98 951 (1,5-CYCLOOCTADIENE)(2,4- 1146 (+)-(S)-N,N-DIMETHYL-1-((R)-1',2- PENTANEDIONATO)RHODIUM(I), BIS(DI- 99% PHENYLPHOSPHINO)FERROCENY 1033 (1,5- L)E CYCLOOCTADIENE)BIS(METHYLD 1142 (+)-(S)-N,N-DIMETHYL-1-((R)-2- IPHENYLPHOSPHINE)IRIDIUM(I)
    [Show full text]
  • The Mechanism of Thiosulfate Oxidation by Thiobacill Us Thioox7dms 8085
    THE MECHANISM OF THIOSULFATE OXIDATION BY THIOBACILL US THIOOX7DMS 8085 BY ROSEMARIE JEFFERY Y. MASAU A Thesis submitted to the Faculty of Graduate Studies in Partial FulFient of the Requirements for the degree of MASTER OF SCIENCE Department of Microbiology University of Manitoba Winnipeg, Manitoba National Library Bibliothèque nationale 1*1 of Canada du Canada Acquisitions and Acquisitions et Bibliographic Services services bibliographiques 395 Wellington Street 395. rue Wellington OîtawaON K1AON4 OttawaON K1A ON4 Canada Canada Your file Votre réUrence Our file Noire refdmce The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sel1 reproduire, prêter, distribuer ou copies of ths thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author7s ou autrement reproduits sans son permission. autorisation. Canada TEE mITYOF MANITOBA FACULTY OF GRADUATE STUDIES ***** COPYRIGHT PERMISSION PAGE The Mechanism of Thiosulfate Ondation by ThiobaciIIzs thwoxiihns 8085 BY Rosemarie Jeffery Y. Masau A Thesislfracticum snbmitted to the Faculty of Graduate Studies of The University of Manitoba in partial fuifiüment of the requirements of the degree of Master of Science Rosemarie Jeffery Y.
    [Show full text]
  • Toxicological Profile for Cyanide
    TOXICOLOGICAL PROFILE FOR CYANIDE U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service Agency for Toxic Substances and Disease Registry July 2006 CYANIDE ii DISCLAIMER The use of company or product name(s) is for identification only and does not imply endorsement by the Agency for Toxic Substances and Disease Registry. CYANIDE iii UPDATE STATEMENT A Toxicological Profile for Cyanide, Draft for Public Comment was released in September 2004. This edition supersedes any previously released draft or final profile. Toxicological profiles are revised and republished as necessary. For information regarding the update status of previously released profiles, contact ATSDR at: Agency for Toxic Substances and Disease Registry Division of Toxicology and Environmental Medicine/Applied Toxicology Branch 1600 Clifton Road NE Mailstop F-32 Atlanta, Georgia 30333 CYANIDE iv This page is intentionally blank. v FOREWORD This toxicological profile is prepared in accordance with guidelines developed by the Agency for Toxic Substances and Disease Registry (ATSDR) and the Environmental Protection Agency (EPA). The original guidelines were published in the Federal Register on April 17, 1987. Each profile will be revised and republished as necessary. The ATSDR toxicological profile succinctly characterizes the toxicologic and adverse health effects information for the hazardous substance described therein. Each peer-reviewed profile identifies and reviews the key literature that describes a hazardous substance’s toxicologic properties. Other pertinent literature is also presented, but is described in less detail than the key studies. The profile is not intended to be an exhaustive document; however, more comprehensive sources of specialty information are referenced. The focus of the profiles is on health and toxicologic information; therefore, each toxicological profile begins with a public health statement that describes, in nontechnical language, a substance’s relevant toxicological properties.
    [Show full text]
  • Caustic Soda Sodium Hydroxide (Caustic Soda), Naoh:  Sodium Hydroxide, Naoh, Is a Soft, Waxy, White, Corrosive Solid
    Caustic Soda Sodium Hydroxide (Caustic Soda), NaOH: Sodium hydroxide, NaOH, is a soft, waxy, white, corrosive solid. It is commonly known as lye or caustic soda. It is one of the important chemicals and is manufactured on a very large scale forming an important chemical industry. It is most conveniently manufactured by one of the following processes: 1. Methods involving sodium carbonate as a starting material. 2. Methods involving sodium chloride as starting material. Methods involving sodium carbonate as a starting material: Two methods are used. These are (i) Causticisation process (Gossage process): Na2CO3 + Ca(OH)2 ⇄CaCO3 + 2NaOH The temperature is maintained 80-90°C by blowing steam. Caustic soda solution is drained out and evaporated to dryness when flakes of caustic soda are obtained. The most suitable concentration of sodium carbonate taken in this process is 15-20%. The caustic soda produced by this method is not pure and contains some calcium carbonate, sodium carbonate and calcium hydroxide as impurities. (ii) Lowig’s process: Na2CO3 + Fe2O3 →2NaFeO2 + CO2 2NaFeO2 + H2O →2NaOH + Fe2O3 The solution is filtered and evaporated to dryness to get flakes of sodium hydroxide. Methods involving sodium chloride as starting material: Methods used are electrolytic as the electrolysis of sodium chloride solution is carried out in an electrolytic cell. Principle: A sodium chloride solution contains Na+, H+, Cl- and OH- ions. NaCI ⇄ Na+ + Cl- + - H2O ⇄ H + OH On passing electricity, Na+ and H+ ions move towards cathode and Cl- and OH- ions move towards anode. The discharge potential of H+ ions is less than Na+ ions, thus hydrogen ions get discharged easily and hydrogen is liberated.
    [Show full text]
  • Chemical Waste Registry – Updated 4/4/13
    Chemical Waste Registry – updated 4/4/13 2-Methyl-2-propanol 08FL 2-PAM 10TX Aatrex 10TX Abate 10TX Acenaphthene 10TX Acepromazine maleate 10TX AcetalÑ 08FL Acetaldehyde 08FL Acetaldehyde ammonia trimer 09FS Acetaldehyde sodium bisulfite 10TX Acetaldoxime 08FL Acetamide 10TX Acetamidine hydrochloride 10TX Acetamidobenzaldehyde, p- 10TX Acetamidobenzoic acid, p- 03CA Acetamino-1,3-dimethylbenzene, 4- 10TX Acetaminophen (2-Hydroxyacetanilide) 10TX Acetanilide 10TX Acetic acid 03CA Acetic acid:methanol 50/50 08FL Acetic anhydride 03CA Acetoacetanilide 10TX Aceto-aceto-toluidide 10TX Acetol (Hydroxyacetone) 08FL Acetonaphthone, 2'- 10TX Acetone 08FL Acetone sodium bisulfite 10TX Acetonedicarboxylic acid, 1,3- 03CA Acetonitrile 08FL Acetophenetidin 10TX Acetophenol 10TX Acetophenone 08FL Acetovanillone 10TX Acetoxime 10TX Acetyl bromide 14WS Acetyl chloride 14WS Acetyl ferrocene 10TX Acetyl fluoride 14WS Acetyl pyridine, 3- 10TX Acetyl-10-chlorophenarsazine, 5- 10TX Acetyl-2-phenyl hydrazine, 1- 10TX Acetyl-2-thiourea 10TX Acetyl-alpha-D-glucosamine, N- 10TX Acetylaminofluorene, 2- 10TX Acetylanthranilic acid, N- 10TX Acetyl-beta-methylcholine chloride 10TX Acetylchlorophenarsazine, N- 10TX Acetylcholine bromide 10TX Acetylcholine chloride 10TX Acetylcholine iodide 10TX Acetylcyclohexanone, 2- 08FL Acetylene 07CG Acetylglycine 10TX Acetylimidazole, 1- 10TX Acetylneuraminic acid 10TX Acetylpenicillamine, N- 10TX Acetylphenoxylacetic acid, p- 03CA Acetylpiperidine, 1- 10TX Acid phosphatase 10TX Acid potassium phthalate 10TX Acotinic acid 10TX
    [Show full text]