Chapter 4. Biological Oxidation

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Chapter 4. Biological Oxidation
Intredction ATP oxidative phosphorylation Oxidatio
n not producing ATP
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• introduction
• ?biological oxidation
• oxidation run in living body, detailedly,
  the process which nutrient substance, such as
  saccharides, lipids, and proteins are oxidized
  into water and carbon dioxide, and simultaneously
  produce energy.

Nutrient O2 ? H2O CO2 energy
ATP heat
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• Characteristics of biological oxidation

biological oxidation burning
temperature 37? high
condition neutral dry
catalyst enzyme no
Velocity of energy release slow fast
Form of energy release ATP heat
Way producing CO2and H2O organic acid decarboxylation produce CO2 wide addition of water and dehydrogenation , the hydrogen combine with oxygen at a indirect way. Oxygen directly combine with carbon(hydrogen), produce CO2(H2O).
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Forms of oxidoreduction in biological oxidation

• oxidizing reaction
• loss of electrons
• dehydrogenation
• addation of oxygen
• reduction reaction
• Gain eletrons
• Addation of hydrogen
• Deoxygenation

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?General course of biological oxidation
glucogen
triglyceride
protein
AcetylCoA
TAC
ADPPi
ATP
CO2
2H
respiratory chain
H2O
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• Energy of reaction

?G lt 0 spontaneous ?G 0 equilibrium ?G gt 0
non-spontaneous
G1
G2
?G G2-G1
?G0 - 2.303 R T log Keg - n F ?E0
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Section 1. ATP
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activation effect
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ATP is the main form of energy utilization and
store in body and the center of energy conversion.
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High-energy compound
????? ????(pH7.0,25?)
UTP?CTP?GTP 30.5 kJ/mol
1,3-??????? ???????? 61.9 kJ/mol
???? 43.9 kJ/mol
??CoA????CoA???CoA 31.4 kJ/mol
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• Transform between high-energy compounds

nucleoside diphosphate kinase
adenylate kinase
ADP ADP ????? ATP AMP
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• creatine phosphate store form of ATP in brain
  and muscle.

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Section 2. oxidative phosphorylation

• Ways producing ATP
• substrate level phosphorylation
• oxidative phosphorylation

substrate level phosphorylation --formation of
ATP by the way of straight transfer high-energy
substrate energy to ADP.
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• 1,3-?????? ADP 3-????? ATP
• ???????? ADP ??? ATP
• ???CoA H3PO4 GDP ??? CoA-SH
  
• GTP
  
  
• 
  
  
  
• ADP
•  
• 
  
• ATP

PK
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I respiratory chain (???) a
oxidoreduction system which consists of a series
of enzyme, coenzyme aligning in mitochondrial
inner membrane, function as linksystem transferer
of hydrogen and electron.
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Mitochondria
Respiratory chain
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electron transfer in respiratory chain
e-
e-
e-
e-
e-
H2O
NADHH
????
1/2O22H
NAD
???
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succinic acid oxidation respiratory chain
NADH oxidation respiratory chain
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Component of respiratory chain
Complex name Number of peptide chain Prosthetic group
Complex? NADH- CoQ reductase 42 FMN, Fe-S
Complex? Succinate-CoQ reductase 4 FAD, Fe-S
Complex? Q-Cyt C reductase 11 Fe-S, iron protoporphyrin,
Complex? Cyt C oxidase 13 Cu, iron protoporphyrin,
? Co-Q and Cyt C
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(1) complex? NADH-Q reducase

• iron-sulphur protein, Flavoprotein with FMN, 42
  peptide chains, 850 kD.
• Bind and oxidize NADH, transfer electrons to Q,
  release 4H to interspace of inner and outer
  membrane.

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Structure of NAD and NADP
RHNAD RH2PO3NADP
NADnicotinamide adenine dinucleotide,CoI NADPn
icotinamide adenine dinucleotide phosphate,CoII
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??????
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ironsulfur protein

• Fe-S

Fe2S2, Fe4S4
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• Ubiquinone,Q
• (Coenzyme Q,CoQ) ??? CoQ10
• quinones contain a polyisoprene side chain.
• liposolubility,make it move in mitochondrial
  inner membrane easily.
• the only one electron carrier without protein in
  respiratory chain.

?
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2H
FMN
Fe-S
N-2
Q
QH2
???????????
2e-
2H
NAD
NADHH
NADHH
FMN
Fe2
Q
FMNH2
Fe3
QH2
NAD
Q
NADH
FMN
Fe-S
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(2) complex?- Succinate-CoQ reductase

• i.e. succinate dehydrogenase, consists at list 4
  peptides. Contain one FAD, two ironsulfur
  protein and one Cyt b560.
• Transfer electron from succinic acid to Q, do not
  release H to the interspace.

succinic acid ?FAD?Fe-S?Q?
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• cytochrome,Cyt ????
• A?structure colourant protein containing iron
  porphyrin.
• B?typing Cyta Cytaa3
• Cytb Cytb562 ?Cytb566? Cytb560
• Cytc Cytc ? c1
• C?difference
• ? different side chain of iron porphyrin.
• Different linkage form of iron porphyrin with the
  protein.

CytFe3 e ? CytFe2
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Difference between Cyt a and Cyt b, Cyt c.
prothetic group color aband wavelength Linkage with protein
Cytb heme red 560nm Non-covalent bonding
Cytc heme red 550nm Bind with SH of Cys
Cyta heme A green 600nm Non-covalent bonding
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(3) Complex ? Q-cytc reducase

• i.e. cyt c reducase, consists of 11 peptide
  chains different, existing as a dimer. every
  monomer contains two cyt b (b562, b566), one cyt
  c1 and a iron sulphur protein.
• Catalyze electron transfer from Q to cyt c. every
  two electronss transfering lead four proton
  pumped to the intermembrance space.

Cytc
QH2
b566?b562?Fe-S?c1
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Cyt c
Complex ?
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Electron transfering process in complex?
first time oxidation of QH2
secondary time oxidation of QH2
Cytc
Cytc
2H
2H
Cytc1
Cytc1
Fe-S
Fe-S
e-
e-
bL
bL
e-
e-
QH2
Q
QH2
Q
bH
bH
? Q
? Q
QH2
Q
2H
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(4) complex ? Cyt c oxidase

• Dimer. Every monomer consists of 13 peptide
  chains different, as 3 subunits I include 2
  heme(a,a3),a cuproprotein (CuB)?include a
  dikaryon center formed by two copper ion(CuA)?
  not clear
• Cu2 e ? Cu

Cyt c
CuA? a ? a3 ? CuB
O2
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NADH?????
NADH?FMN(Fe-S)?Q?b?c1?c?aa3?O2
????????
succinic acid?FAD(Fe-S)?Q?b?c1?c?aa3?O2
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overall reaction
or
further
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?????????????????

• ?????????????????????4????,??Q?????C?ATP???
• ????????E0?????
• ????????????????????????
• ?????????
• ??????????????

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II?oxidative phosphorylation
oxidative phosphorylation refer to the ATP
producing form which the reaction ADP change into
ATP couple with respiratory chain oxidation. It
is main form of ATP producing in body.
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Why does the reaction ADP Pi ? ATP H2O
request a couple?
The product state(ATPH2O) is higher energy
level than reactant state(ADP Pi). So, ADP
change into ATP isnt spontaneous process. Energy
obtaining is requested for the process.
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• Which segment in respiratory chain can produce
  enugh energy for ADP phosphorylation?

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Whats P/O ratio?Whats its meaning?

• --- number of moles of ATP produced as
  consuming a mole of oxygen atom in a reaction,
  i.e. the number of moles of phosphor cosumed
  when consume a mole of oxygen atom in the
  reaction.

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• Whats the way of ADP phosphorylation coupled
  with respiratory chain oxidation?

• ??????????????????????????????????????????????
  ???

• Chemiosmotic hypothesis
• the energy of respiratory chain oxidation change
  into proton gradient across the inner membrane.
• the proton gradient drive ATP-synase produce ATP.

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In electron transfer process, respiratory
chain put proton to intermembrance of inner and
outer membrance, result in proton concentration
different of the two side of the inner membrance.
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conceptual diagram of Chemiosmotic hypothesis
H
H
H
H
H
H

- - - - - - - - - - - - - -
-
e-
????
H2O
NADHH
???
1/2O22H
NAD
ATP
ADPPi
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ATP synase

• Consists of hydrophobic F0(a1b2c9?12)and
  hydrophilic F1(?3?3???).
• When proton go straight through a,push c loop
  turning , and as a result, spur the F1 turning.
  

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Position of ATP synase in mitochondria
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work principle of ATP









synase
Three conformations of ?subunit?L,?T,?O
Procedure of ATP production
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?. Factors affecting oxidation phosphorylation

• Inhibitors
• Regulation by ADP
• Thyroid hormone
• Mitchondrial DNA mutation

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(1)Inhibitors

• Inhibitors of respiratory chain
• block electron transfer of respiratory
  chain.
• Uncoupler
• destroy the coupling of oxidation with
  phosphorylation, like uncoupling protein,
  2,4-dinitrophenol.
• Inhibitors of oxidative phosphorylation
• restrain the proton return to matrix side in
  ATP synase, like oligomycin

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Blocking sites of inhibitor of respiratory chain
CO?CN-?N3-?H2S
???A ?????
?
?
?
??? ????A ?????
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Machanism of uncoupling
?????
?
H
ADPPi
H
ATPH2O
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inhibitory action of oligomycin
stop proton flow from F0 proton channel.
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• (2) regulation by ADP
• main regulation factorADP/ATP ratio
• ADP Pi ? ATP H2O

Respiratory control ratio ???????,???????,??ADP???
????????????????
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(3). Thyroid Hormone
Thyroid Hormone ?????
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(4) Mitchondrial DNA mutation
function of mitochondrium
Mitochondrium diseases

• all of the 13 peptides (7 peptides in NADH
  dehydrogenase, 1 in Cytc reducase, 3 in Cyt c
  oxydase,2 in ATP synase coded) by Mitochondrium
  join in oxidative phosphorylation.
• Mutation affect oxidative phosphorylation, ATP
  production decrease.
• Naked cyclic duble helix DNA, lack of defend
  system and restoration system.
• Symptoms are dependent on the degree of mutation
  and the different organs need for ATP.

• Maternally inherited diseases (heritage neurosis,
  heritage diabetes and deafness)
• Aging related

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IV? Mitochondria Entry and Exit of Molecules
Mitochondrial porin, the major protein of the
outer mitochondrial membrane, allows molecules
less than 10 kD to pass
Inner membrance were controled by differnet
transporter.
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Oxidation of NADH in cytosol

• a-glycerophosphate shuttle
• (a-??????)
• malate-asparate shuttle
• (???-??????)

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Comparison of the two ways of NADH oxidation
???? ??????? ????? ??????????? ???????????? ???????????? ????????ATP?
?-?????? ???????? a-??????? NAD FAD ???????? 2ATP
????? ?????? ?????? NAD NAD NADH????? 3ATP
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?-glycerol phosphate shuttle
???
NADHH
FADH2
NAD
FAD
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• malate-asparate shuttle

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?. aerobic dehydrogenase and oxydase
Section 3. other oxidation system
hydrogen acceptor prosthetic group product example
?????? ?? NADH???
????? O2 FMN(FAD) H2O2 ??????? ????????????
??? O2 ?Cu H2O ????c???????? ????????
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?. Erzymes in peroxisome ?????????

• (1).catalase ?????
• catalytic reaction one molecule H2O2 offer
  electronanother molecule H2O2 accept electron.
• prosthetic group 4 heme
• Function wide distribution, wipe out toxical H2O2

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(2). peroxidase (?????)

• Catalytic reactioncatalyze H2O2 straight oxidize
  phenols and amines
• prosthetic group1 heme
• Protect body. glutathione peroxidase
• Clinical diachorema occult blood test

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? . superoxide dimutase, ( SOD,???????)

• ????????????????(O2-.)
• O2-. H2O2 .OH
• ???????????

SOD
2O2-. 2H H2O2 O2
H2O O2
?????
SOD???Cu?Zn(??) ?Mn(???)?
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(1). monooxygenase (????)
?. Oxidases in microsome
Catalytic reaction

• mixedfunction oxidase(???????)
• or Hydroxylase(???).

composition NADPH-Cytc reducase,
flavoprotein(FAD), ironsulfur protein(Fe2S2)?CytP4
50?
functionhydroxylation??????????????????????????
????????????
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• mechanism

RH.P450.Fe3
RH
H2O
ROH
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(2). dioxygenases (????)

• incorporate both oxygen atoms into the
  substrate.

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??

• ATP?????????????
• ??????????????????????????????????????????????????
  ?NADH?FMN(FeS)?Q?b?c1?c? aa3 ? O2
• ?????FADH(FeS)?Q?b?c1?c?aa3?O2
• ???????????????????NADH?QCtyb?CytcCytaa3?O2
• ??????
• ??????????
• ??????????????????????SOD?????????????

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????

• 1. ??????( )
• A ??? B ????? C ????? D ??? E ??????
• 2.????????NADH????????? ( )
• A. FMN B. FAD C. ?? D. ???? E. ????c
• 3. ATP????????( )
• A ????? B ????? C ????? D ???????
• 4 ??????????,?????????( )??ATP?
• 5 ????????????,????( )
• A ??????????B ?????????ATP
• C ?????????????D ?ATP????????????
• 6?????????????????????( )
• A ?????? B ?????? C ??????D ????c???

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7 ????????????????? 8 ??????????????????? ???? ??
? ??????
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