Microbial Metabolism

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Microbial Metabolism

• Biochemical diversity

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Metabolism Relationships
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Metabolism Pathways
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Metabolism

• Define
• Requirements
• Energy
• Enzymes
• Rate
• Limiting step
• Reaction time
• Types
• Anabolic
• Endergonic
• Dehydration
• Biosynthetic
• Catabolic
• Exergonic
• Hydrolytic
• Degradative
• /- metabolites

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Metabolic Diversity

• Energy generating metabolism
• Fermentation
• Alcohol
• Acid Formation
• Lactic Acid
• Mixed Acids
• Others
• Respiration
• Aerobic
• Anaerobic
• Biosynthesis of secondary metabolites
• Heterotrophic
• Autotrophic

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Energy

• Forms
• Kinetic
• Potential
• Use
• Chemical
• Mechanical
• Electrical
• Radiation EM
• Chemical Types
• ATP
• UTP
• GTP
• Heat
• Byproduct
• 45

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Various Types of Prokaryotic Energy Production
Processes

• Fermentation
• Anaerobic Respiration
• Aerobic Respiration
• Lithotrophy
• Photoheterotrophy
• Anoxygenic photosynthesis
• Methanogenesis

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Enzymes

• Structure
• Protein
• Ribozyme ribosome
• Characteristic functions
• Active site
• Specific
• Modified Forms
• Inactive
• Active
• Coenzyme/Cofactor
• -ase

Polymerase
Others Lyases, Hydrolases, Isomerases,
Transferases
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Enzyme Characteristics
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Enzyme Structure

• Apoenzyme
• Protein
• Allosteric site
• Cofactor
• Metal ions
• Cu
• Zn
• Mg
• Fe
• Ca
• Co
• Mn
• Coenzyme
• Vitamins
• CoA
• NAD
• NADP
• FAD

?Allosteric site
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Factors Affecting Enzymes

• Temperature
• pH
• Acids/Bases
• UV light
• Concentration of substrates (saturation)
• Inhibitors

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Enzyme Inhibitors

• Classified
• Competitive
• _at_ active site
• Similar shape
• Binding
• Irreversible
• Reversible
• Noncompetitive
• _at_ allosteric site
• Change shape
• Binding
• Irreversible
• Reversible

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Noncompetitive Enzyme Inhibition
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Enzyme Inhibition Summary
Noncompetitive at Allosteric site
Competitive at active site
Excitatory Inhibitory
Reversible Irreversible
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Glycolysis Embden-Meyerhoff

• Glycolytic
• Cytoplasm
• Anaerobic
• End products
• 2 Pyruvic acids
• 4-2 2 net ATP by substrate level
  phosphorylation
• 2 NADH
• 2 H20

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Lactic Acid Formation
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Glycolysis PPP

• Breakdown 5-6 C
• Cytoplasm
• Anaerobic
• End products
• 1 ATP
• 2 NADPH
• CO2
• 4,5,6,7 C
• AA
• Nucleotides
• Glycolytic pathways
• Photosynthesis

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Glycolysis Entner-Duodoroff E-D

• Glycolytic
• Cytoplasm
• Anaerobic
• Different enzymes
• Pseudomonas
• Enterococcus
• End products
• 2-1 1 net ATP
• NADPH
• NADH
• 2 Pyruvic acids
• H20

NADP NADPH
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Anaerobic Pathways Compared
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Glycolytic Pathways used by various Bacteria
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Anaerobic Processes

• Lactic Acid
• Lactobacillus
• Mixed Acid
• Enterobacteriaceae
• Butanediol
• Klebsiella
• Enterobacter
• Butyric Acid
• Clostridia
• Butanol-Acetone
• Clostridia
• Propionic Acid
• Corynebacteria

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Fermentation
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Fermentation Pathways
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Fermentation Summary

• Anaerobic
• Cytoplasm
• Partial Oxidation
• Small amounts of ATP generated via substrate
  level phosphorylation
• Organic intermediaries as final electron
  acceptors
• End products
• Acid Lactic Acid, Acetic Acid, Butyric Acid,
  Acetone
• Alcohol Ethanol, Isopropyl
• Gas CO2, H2
• Contaminants

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Summary
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Carbohydrate Fermentation Tests
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Phosphorylation

• Substrate Level
• Direct transfer of phosphate
• Glycolysis
• Oxidative Phosphorylation
• Electron transfer
• Chemiosmosis
• Photophosphorylation
• Light energy to chemical energy

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Substrate Level Phosphorylation
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Aerobic Respiration
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Mitochondria of Eukaryotes
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Plasma cell membrane
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(No Transcript)
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Acetyl CoA Formation
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Acetyl CoA Final Structure
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Krebs CycleTCA/Citric Acid
Eukaryotic Mitochondria Or Prokaryotic Cytoplasm
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Oxidation in Krebs Cycle
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Krebs Cycle Metabolites

• For every AcetylCoA
• 2 CO2
• 3 NADH
• 1 FADH2
• 1 ATP (substrate level phosphorylation from GTP)
• Regenerates
• CoA
• Oxaloacetic acid

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Dehydrogenation

• Use of hydrogen in oxidative reactions
• Removal of electron from hydrogen
• Carried on vitamin B derivatives
• Energy released is trapped in chemical bonds

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Redox Reactions
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Oxidation
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Reduction
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Catabolism Anabolism
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Eukaryotic ETC
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Prokaryotic ETC
Vit B2 Riboflavin based Flavoproteins Metal
Proteins with ions (Fe, S, Cu) Iron based
Cytochromes (b,c1,c,a,a3) Ubiquiones based on Vit
K (CoEnzyme Q)
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ETC Steps

• Electrons from NADH or FADH2 to flavoproteins
  (FMN)
• H pumped into periplasm
• Electrons transported
• To Iron-Sulfur proteins from NADH
• To CoQ from FADH2
• Cytochromes transfer electrons
• Final Electron Acceptor
• O2 if Aerobic
• Other inorganic molecule if Anaerobic

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Proton Pump
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ETC NAD ?NADH H
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ETC Cytochromes
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Cytochrome Oxidase (Cyt a Cyt a3)
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Oxidase Test
Oxidase () Pseudomonas Oxidase (-) E.coli,
Proteus
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ATP Synthetase
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Anaerobic Respiration

• Use of another compound than O2 as final electron
  acceptor in the ETC
• Examples
• Nitrate ion NO3- Pseudomonas, E coli, Bacillus
• NO2-
• N2O
• N2
• Sulfate ion SO4 to H2S
• Methanogens
• Carbonate ion CO3 to CH4
• Methanogens

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Nitrogen Reduction Test
Nitrate Reduction with Zinc
Nitrate Reduction Neg with zinc
Nitrate Reduction
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Other Catabolic Processes

• Protein
• Deamination
• Decarboxylation
• Dehydrogenation

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Other Catabolic Processes

• Lipid
• Glycerol
• FA
• Beta oxidation
• Acetyl CoA

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Biosynthesis

• Polysaccharide
• Keto acids
• AA
• Glycerol from FA
• Lipid
• Glycerol FA
• AA
• Keto acids NH2
• Nucleotides
• Nitrogen bases from Keto acids NH2
• 5 C sugars from alternate CH20 Metabolism

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Functions

• Polysaccharide
• Cell wall components
• LPS
• Lipid
• Cell wall
• Plasma membranes
• AA/Protein
• Cell wall / membrane components
• Enzymes
• Toxins
• Nucleotide
• DNA
• RNA
• ATP
• NAD
• NADP

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Protein Synthesis and Enzyme Regulation
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Metabolism Summary
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Questions?