METABOLISM

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METABOLISM part A
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• Metabolism refers to all the chemical reactions
  which occur in life.
• These reactions are
• 1. Catabolic - degradative reactions which
• a. Convert food into twelve, key, low molecular
  weight intermediates (which can be converted in
  anabolic reactions into low molecular weight
  precursors of proteins, polysaccharides,
  lipids, and polynucleotides).
• b. Oxidize food, generating NADH H, which
  transfers electrons to the electron transport
  chain, with resulting ATP generation.
• c. Convert food into low molecular weight
  compounds which can serve to generate ATP by
  substrate level phosphorylation.
• 2. Anabolic - biosynthetic reactions which
  generate amino acids, fatty acids,
  monosaccharides, and mononucleotides and
  polymerize them into proteins, lipids,
  polysaccharides, and polynucleotides.
• B. Sets of reactions in which the product of one
  reaction serves as the substrate for the next
  reaction are called pathways. For example,
  compound A might be converted into compound E
  by four, successive reactions.
• C. Enzymes are necessary to catalyze most
  biochemical reactions so that the reaction
  reaches equilibrium within a time scale useful
  for life. Enzymes usually are proteins they
  usually catalyze one, specific reaction usually
  every reaction requires catalysis by one specific
  enzyme.
• Although a given reaction, such as A B C
  D, might come to equilibrium, in the test tube,
  with only slightly more C D formed than the
  amount of A B remaining, in living organisms,
  this reaction usually goes to completion. This is
  possible because C or D is removed by, for
  example, conversion to some other product -if C
  or D is not removed, the reaction comes to
  equilibrium.

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OVERVIEW - ANABOLISM, CATABOLISM ENERGY Free
Energy Change Exergonic, Endergonic Enzymes -
Catalyst, Activation Energy Enzymes - Bind
substrates Strain specific bonds in
substrates Lower activation
energy Apoenzyme plus coenzyme
holoenzyme Example - Aldolase (High
Molecular Weight, Protein) Fructose- 1,
6-bisphosphate gt Dihydroxy acetone phosphate plus
Glyceraldehyde-3-phosphate OXIDATION/REDUCTION
REACTIONS - REDOX Oxidation - loss of electron
- electron donor Reduction - gain of electron -
electron acceptor Coupled Oxidation/Reduction
reactions ELECTRON CARRIERS Nicotinamide
adenine dinucleotide NAD - coenzyme involved in
oxidation/reduction NAD plus 2e- plus 2H lt
gt NADH plus H Oxidized Reduced Reducing
Power ENERGY LEVEL OF PHOSPHATE-CONTAINING
COMPOUNDS Esters - low energy glucose-6-ph
osphate Anhydrides -high energy ATP,
adenosine triphosphate - Universal source of high
energy 1,3-diphospho glyceric acid -
(1,3-diphospho glycerate)
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GLYCOLYSIS - glucose conversion to pyruvate
Embden-Meyerhoff Pathway NADH plus H
generated Substrate level phosphorylation RESPI
RATION - pyruvate conversion to carbon dioxide
plus water in aerobic respiration NADH plus
H, FADH2, GTP generated Flow of electrons to
Electron Transport Chain Oxidative
Phosphorylation Terminal Electron Acceptor
(Oxygen in aerobic respiration) FERMENTATION -
Pyruvategt Lactic Acid (lactate) Pyruvategt
Ethanol plus CO2 Glycolysis plus fermentation
Allow glucose conversion to lactate or ethanol
with internally balanced redox reactions. Do not
require terminal electron acceptor. Result in
only partial oxidation of glucose carbons.
Yield only small amount of potential energy of
glucose. Allow ATP generation by substrate level
phosphorylation. GLYCOLYSIS PATHWAY FERMENTATION
PATHWAYS - Pyruvate to lactate, Pyruvate to
ethanol plus carbon dioxide
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G-6-PO4 ATP
LOW MOLECULAR WEIGHT BUILDING BLOCKS
MACROMOLECULES
AMINO ACIDS FATTY ACIDS MONOSACCHARIDES MONONUCLEO
TIDES PROTEINS-ENZYMES FLAGELLIN RIBOSOMES
ETC. PHOSPHOLIPIDS POLYSACCHARIDE
PEPTIDOGLYCAN DNA/RNA t,r,m
CHEMICAL SYNTHESIS FOOD TRANSPORT MOTILITY
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G - FREE ENERGY - ENERGY RELEASED IN FORM
ABLE TO DO WORK DG' CHANGE IN FREE ENERGY
UNDER STANDARD CONDITIONS NEGATIVE DG -
EXERGONIC FREE ENERGY RELEASED
REACTION OCCURS SPONTANEOUSLY EQUILIBRIUM
FAVORS RIGHT
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POSITIVE DG - ENDERGONIC FREE ENERGY
REQUIRED REACTION WILL NOT OCCUR
SPONTANEOUSLY EQUILIBRIUM FAVORS LEFT
DG - DOES NOT PREDICT HOW LONG WILL BE REQUIRED
TO REACH EQUILIBRIUM
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• ENZYMES 108 - 1020 x RATE
• BIND SUBSTRATE
• HOLD SUBSTRATE IN ENZYME CATALYTIC SITE-STRAIN
  BONDS
• REDUCE ACTIVATION ENERGY

NO ENZYME
NO ENZYME
DG
PLUS ENZYME
G
ENZYME
ACTIVATION ENERGY
SUBSTRATE
PRODUCT
(Not a time scale)

• ENZYME DOES NOT CHANGE
• FREE ENERGY OF SUBSTRATE/PRODUCT
• EQUILIBRIUM DG IS THE SAME /- ENZYME

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ENZYME - TURN OVER NUMBER - NUMBER OF MOLECULES
OF REACTANT (SUBSTRATE) CONVERTED TO PRODUCT PER
MOLECULE OF ENZYME PER UNIT OF TIME (e.g.,
SECOND) TYPICAL 2,000 / SECOND 120,000 /
MINUTE
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ENZYME - ALDOLASE

ENZYME - SUBSTRATE COMPLEX
FRUCTOSE-1,6- BISPHOSPHATE
DI-HYDROXY ACETONE PHOSPHATE


GLYCERALDEHYDE -3-PHOSPHATE
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ENZYME - ALDOLASE

ENZYME - SUBSTRATE COMPLEX
ALDOLASE SPLITS HERE BREAKS TWO BONDS FORMS TWO
MOLECULES
FRUCTOSE-1,6- BISPHOSPHATE
DI-HYDROXY ACETONE PHOSPHATE
ALDOLASE 359 a.a. MW 39,147


GLYCERALDEHYDE -3-PHOSPHATE
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OXIDATION - LOSS OF ELECTRON REDUCTION - GAIN OF
ELECTRON
REDUCING AGENT
OXIDIZING AGENT
SUMMARY
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NICOTINAMIDE ADENINE DINUCLEOTIDE
NADH H NAD 2e
2H
IS OXIDIZED
OXIDIZED STATE
TRANSFERS e- TO OTHER CARRIERS TO GENERATE ATP
REDUCED STATE
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NAD
NADH H
H
2e 2H REDUCED OXIDIZED
NICOTINAMIDE ADENINE DINUCLEOTIDE
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b-D-GLUCOSE-6-PHOSPHATE ESTER LOW ENERGY
ADENOSINE TRIPHOSPHATE ANHYDRIDE HIGH ENERGY
1,3 DIPHOSPHO GLYCERIC ACID ANHYDRIDE
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GLUCOSE
2 PYRUVATES
6CO2
RESPIRATION (AEROBIC)
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FERMENTATION
NOTE NAD RECYCLES
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SUBSTRATE LEVEL PHOSPHORYLATION
ATP (PLUS LOW MOLECULAR WEIGHT COMPOUND)
LOW MOLECULAR WEIGHT - PO4 CONTAINING COMPOUND
ADP
OXIDATIVE PHOSPHORYLATION

• NADH H TRANSFER ELECTRONS
• TO ELECTRON TRANSPORT CHAIN
• ELECTRON FLOW IS COUPLED TO ATP SYNTHESIS
• ADP Pi ATP
• REQUIRES TERMINAL ELECTRON ACCEPTOR
• e.g., O2

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SUBSTRATE LEVEL PHOSPHORYLATION
PHOSPHO - ENOL PYRUVATE
ENZYME - PYRUVATE KINASE
PYRUVATE
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GLYCOLYSIS
GLUCOSE
ATP
ADP
GLUCOSE-6-PO4
FRUCTOSE-6-PO4
ATP
ADP
FRUCTOSE-1,6-BISPHOSPHATE
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DIHYDROXY ACETONE PHOSPHATE
GLYCERALDEHYDE -3-PHOSPHATE
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GLYCOLYSIS
GLYCERALDEHYDE -3-PHOSPHATE
NAD
e-
NADH H REDUCING POWER
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SUBSTRATE LEVEL PHOSPHORYLATION
1,3 BISPHOSPHO-GLYCERATE
ADP
ATP
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3-PHOSPHO-GLYCERATE
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GLYCOLYSIS
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C OH
OH
HIGHER ENERGY THAN ANHYDRIDE
C O P
2-PHOSPHO GLYCERATE
OH
O
H C
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PHOSPHOENOL PYRUVATE
O
PYRUVATE
C OH
SUBSTRATE LEVEL PHOSPHORY-LATION
C O
CH3
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LACTIC ACID FERMENTATION
PYRUVATE
NADH H
REDUCED
NAD
e-
NET GLUCOSE 2 LACTATE 2 ADP 2 Pi 2
ATP
LACTATE
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ETHANOL FERMENTATION
CO2
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METABOLISM parts B C
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METABOLISM - PART B RESPIRATION - Aerobic,
terminal electron acceptor is O2 ELECTRON
TRANSPORT CHAIN (SYSTEM) - Accept electrons
from electron donors and transfer to
acceptors Energy released during electron
transfer used for ATP synthesis CHEMIOSMOSIS -
PROTON MOTIVE FORCE pH Gradient H and OH-
membrane bound H ATPase ADP Pi form ATP
(reversible) TRICARBOXYLIC ACID
CYCLE Pyruvate, coenzyme A, acetyl
CoA NAD conversion to NADH
H FAD/FADH2 CO2
METABOLISM - PART C MODES OF ENERGY
GENERATION Aerobic respiration, Anaerobic
respiration Chemolithotrophic
metabolism Phototrophic metabolism ANABOLISM
- BIOSYNTHESIS Low Molecular Weight Building
Blocks (Precursors of Macromolecules) Twelve
key, central metabolites Pentoses Amino
Acids - Alanine (from Pyruvate) Tryptopha
n (from Phosphoenolpyruvate and
erythrose-4-phosphate)
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AEROBIC RESPIRATION
PYRUVATE
NAD
CoA
NADH H
CO2
CoA
Q
OXALO- ACETATE
CITRIC ACID (C6)
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4
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ENERGY YIELD FROM PYRUVATE OXIDATION
1 PYRUVATE 3 CO2 1 NAD 4 NADH H 12 ATP 1
FAD 1 FADH2 2 ATP 1 GDP 1 Pi 1 GTP 1
ATP 15 ATP
EQUIVALENT TO
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ELECTRON TRANSPORT CHAIN (SYSTEM)
1. ACCEPTS e- FROM DONORS NADH FADH2 2. USES
ENERGY RELEASED IN OXIDATION/ REDUCTION
REACTIONS TO ENERGIZE MEMBRANE AND SYNTHESIZE ATP
RE-DOX ENZYMES

1. NADH DEHYDROGENASES
2. FLAVO PROTEINS
3. IRON-SULFUR PROTEINS
4. QUINONES (NON - PROTEINS)
5. CYTOCHROMES

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REDUCTION POTENTIAL E'O
-0.4 SUBSTRATES, AS GLYCERALDEHYDE-3-PHOSPHATE -0.
3 NADH, NADH DEHYDROGENASE -0.2 FLAVOPROTEIN -0.1
IRON SULFUR PROTEINS QUINONES 0 CYTOCHROMES 0.
4 NO3- NO2- 0.8 OXYGEN O2
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CHEMIOSMOSIS - GENERATES PMF (PROTON MOTIVE FORCE)
NDH NADH DEHYDROGENASE
pH GRADIENT ENERGIZES CM PMF GENERATED
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ENERGIZED MEMBRANE - SYNTHESIZES ATP ROTATES
FLAGELLA
OUTSIDE THE MEMBRANE
H
H
H
H
H
H
H
H
OH-
OH-
OH-
OH-
ADP Pi
ATP
ATP SYNTHASE
INSIDE THE MEMBRANE
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ATP SYNTHASE
ADP Pi H ATP H2O
ANHYDRIDE
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YIELD - GLYCOLYSIS RESPIRATION
GLYCOLYSIS 1 GLUCOSE 2 PYRUVATES
INPUT 2ATP YIELD
SUBSTRATE LEVEL PHOSPHORYLATION 4 ATP 2 NADH
ETC 6 ATP
AEROBIC RESPIRATION 2 PYRUVATES 6O2 6CO2
6H2O
8 NADH 24 ATP 2 FADH2 4 ATP 2 GTP
EQUIVALENT 2 ATP GROSS 40
ATP NET 38 ATP
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ACTIVE TRANSPORT (FOOD)
FLAGELLA ROTATION
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NUTRITION AND RESPIRATION MODES
FOOD
ELECTRON ACCEPTOR O2 H2
O NO3- NO2- NO2- N2 SO4- - SO3-
- SO3- - H2S O2 H2 O NO
TERMINAL e- ACCEPTOR e- FLOW IS CYCLIC
MODE AEROBIC ANAEROBIC CHEMO-LITHOTROPHIC
PHOTO-TROPHIC
CARBON ORGANIC COMPOUNDS ANABOLISM ORGANIC
COMPOUNDS CO2 ALL ORGANIC COMPOUNDS CO2 ALL
ORGANIC COMPOUNDS
ENERGY ORGANIC COMPOUNDS OXIDATION TO
CO2 ORGANIC COMPOUNDS H2 H2S NH3 LIGHT
PROVIDES ENERGY
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PHOTOTROPHIC NUTRITION AND RESPIRATION PLANTS
AND CYANOBACTERIA - OXYGENIC, EVOLVE OXYGEN FROM
H2O ANOXYGENIC PHOTOSYNTHETIC BACTERIA - DO NOT
GENERATE O2 - HAVE BACTERIOCHLOROPHYLL
EXCITED B Ch P
PROTON DONORS H2S SUCCINATE
LIGHT
PROTON GRADIENT- PROTON MOTIVE FORCE ATP
SYNTHESIS
BACTERIO-CHLOROPHYLL B Ch P
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NITROGEN FIXATION
RHIZOBIUM - LEGUMES AZOTOBACTER - FREE LIVING
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ORGANIC COMPOUNDS (GLUCOSE)
BY-PRODUCTS (WASTE)
CATABOLISM
ATP
SIMPLE COMPOUNDS 12 KEY, CENTRAL METABOLITES
ANABOLISM
LOW MOLECULAR WEIGHT PRECURSORS OF MACROMOLECULES
ANABOLISM
CELLULAR CONSTITUENTS
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ORGANIC COMPOUNDS
HETEROTROPHS
GLUCOSE-6-PHOSPHATE FRUCTOSE-6-PHOSPHATE RIBOSE-5-
PHOSPHATE ERYTHROSE-4-PHOSPHATE DIHYDROXY-ACETONE
PHOSPHATE 3-PHOSPHOGLYCERATE PHOSPHOENOL
PYRUVATE PYRUVATE ACETYL-CoA aKETOGLUTARATE SUCCIN
YL-CoA OXALOACETATE
MONO AND DISACCHARIDES
AMINO ACIDS
POLY- SACCHARIDES
PROTEIN
FATTY ACIDS
MONO-NUCLEOTIDES
LIPIDS
RNA, DNA
VITAMINS
LIST IS NOT ASSIGNED
AUTOTROPHS
CO2
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GROUP TRANSLOCATION
PHOSPHO TRANSFERASE SYSTEM - SUGARS ENERGY
- PHOSPHO ENOL PYRUVATE - PEP FULL NAME IS
PHOSPO ENOL PYRUVATE SUGAR PHOSPHOTRANSFERASE
SYSTEM SOME SUGARS TRANSLOCATED
GLUCOSE, FRUCTOSE, MANNITOL,
SUCROSE ENZYMES TAKE PHOSPHATE FROM
PEP TRANSLOCATE SUGAR FROM PERIPLASM
INTO CYTOPLASM, TRANSFERRING PHOSPHATE
TO TO IT IN THE PROCESS EACH ENZYME
SYSTEM IS SPECIFIC FOR INDIVIDUAL SUGAR
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(No Transcript)
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PENTOSE BIOSYNTHESIS
GLUCOSE-6-PHOSPHATE
RIBOSE-5-P
CO2
GLUCOSE-6-P
RIBULOSE-5-P
HEMI ACETAL FORM
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ALANINE SYNTHESIS
TRANSAMINASE
PYRUVATE
L-ALANINE
L-GLUTAMATE
a-KETO-GLUTARATE
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CHORISMATE FROM "KEY METABOLITES"
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PHOSPHOENOL PYRUVATE
ERYTHROSE- 4-PO4

6 REACTIONS AND 6 ENZYMES
CHORISMIC ACID (CHORISMATE)
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TRYPTOPHAN BIOSYNTHESIS
ANTHRANILATE
CHORISMATE
PHOSPHO RIBOSYL PYROPHOSPHATE
PHOSPHO RIBOSYL ANTHRANILATE
CARBOXY PHENYL AMINO- DEOXY RIBULOSE-5-P
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GLYCERALDEHYDE-3- PHOSPHATE
SERINE
INDOLE GLYCEROL PO4
L-TRYPTOPHAN