TheMcGraw-HillCompaniesChapter 8AnIntroductiontoMicrobialMetabolismFoundationsinMicrobiologyEIGHTHEDTTIOKathleenParkTalaroBarryChessCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Chapter 8 An Introduction to Microbial Metabolism Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
FEXTheMetabolismofMicrobesCopyright The McGrawHill Comparies, Inc. Permission required for reproduction or displayMetabolism - all chemical andSynthesis of Cell Structuresphysical workings of a cellMacromoleculesSourcesofenergyCarbohydratesCarbohydratesProteinsLipidsLipidsProteinsTwo types of chemical reactions:Catabolism- degradative;CatabolismAnabolismReleases energyATPRequires energyNADHbreaks the bonds of largeraemolecules forming smallerSimple buildingEndproductswithblocksmolecules; releases energyreduced energySugarsCO2, H:OAmino acidsAnabolism-biosynthesis;process that forms largermacromoleculesfromsmallermolecules;requiresenergy input2
2 The Metabolism of Microbes Metabolism – all chemical and physical workings of a cell Two types of chemical reactions: Catabolism – degradative; breaks the bonds of larger molecules forming smaller molecules; releases energy Anabolism – biosynthesis; process that forms larger macromolecules from smaller molecules; requires energy input Synthesis of Cell Structures Sources of energy Carbohydrates Lipids Proteins End products w ith reduced energy CO2, H2O Macromolecules Carbohydrates Proteins Lipids Simple building blocks Sugars Amino acids Catabolism Releases energy Anabolism ATP Requires energy NADH Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Increasing complexity
FEXEnzymesEnzymes are biological catalysts that increase the rate of achemical reaction by lowering the energy of activation (theresistance to a reaction)The enzyme is not permanently altered in the reactionEnzyme promotes a reaction by serving as a physical sitefor specific substrate molecules to positionCopyright The McGraw-HllCompanies, hc. Permission required for reproduction or displayEnergyofactivationintheabsenceofenzymeReactantEnergyof activationinthe福presenceofenzymeInitialstateProductsA?3Final stateProgress ofReaction
3 Enzymes • Enzymes are biological catalysts that increase the rate of a chemical reaction by lowering the energy of activation (the resistance to a reaction) • The enzyme is not permanently altered in the reaction • Enzyme promotes a reaction by serving as a physical site for specific substrate molecules to position Progress of Reaction Energy of activation in the absence of enzyme Energy of activation in the presence of enzyme Products Final state Reactant Initial state Energy State of Reaction Copyright © The McGraw -Hill Companies, Inc. Permission required for reproduction or display
EnzymeStructure Simple enzymes - consist of protein aloneConjugated enzymes or holoenzymescontain protein and nonprotein molecules-Apoenzyme -protein portion- Cofactors - nonprotein portion.Metalliccofactors:iron, copper,magnesium. Coenzymes, organic molecules: vitaminsCopyright The McGraw-HillCompanies, Inc. Permission required for reproduction or displayCoenzymeCoenzymeMetalliccofactorMetallic4cofactorApoenzymes
4 Enzyme Structure • Simple enzymes – consist of protein alone • Conjugated enzymes or holoenzymes – contain protein and nonprotein molecules – Apoenzyme – protein portion – Cofactors – nonprotein portion • Metallic cofactors: iron, copper, magnesium • Coenzymes, organic molecules: vitamins Coenzyme Apoenzymes Coenzyme Metallic cofactor Metallic cofactor Copyright © The McGraw -Hill Companies, Inc. Permission required for reproduction or display
EnzymeExamplesandtheirCofactorsCopyrightTheMcGraw-Hill Companies, Inc.Permission required forreproductionordisplay.TABLE8.2SelectedEnzymes,CatalyticActions,and CofactorsMetallicCofactorEnzymeActionRequiredCatalaseIron (Fe)Breaksdownhydrogen peroxideOxidaseAdds electrons toIron, copper (Cu)oxygenHexokinaseTransfers phosphateMagnesium (Mg)to glucoseUreaseNickel (Ni)Splits urea into anammoniumionNitrate reductaseReduces nitrateMolybdenum (Mo)tonitriteDNA polymeraseSynthesis of DNAZinc (Zn) and Mg5complex
5 Enzyme Examples and their Cofactors