This document discusses high and low energy phosphates and adenosine triphosphate (ATP). It provides data on the free energy released by different phosphates. It then describes the importance of ATP as the primary energy currency in cells and its role in transferring phosphate energy. The document also discusses electron carriers in the electron transport chain, including protein-bound carriers like cytochromes and mobile carriers like coenzyme Q. It outlines the five complexes of the electron transport chain and chemiosmotic coupling for oxidative phosphorylation. Finally, it mentions ATP synthase and inhibitors of the electron transport chain and oxidative phosphorylation.

1. Dr. V. SivaPrabodh
MD.
Professor

3. High energy phosphates &Low energy phosphates:
Compound
Phosphoenolpyruvate -14.8
Carbamoyl phosphate -12.3
1,3 – Bisphosphoglycerate -11.8
Creatine phosphate -10.3
ATP ADP + Pi -7.3
ADP AMP + Pi -6.6
Pyrophosphate -6.6
Glucose 1-phosphate -5.0
Fructose 6 –phosphate -3.8
AMP -3.4
Glucose 6 –phosphate -3.3
Glycerol 3-phosphate -2.2
Kcal/mol
-7.3ATP ADP +Pi

4. Adenosine Triphosphate (ATP)

5. Importance of Adenosine Triphosphate (ATP)
 ATPservesasthegeneral "freeenergy currency" for
virtually all cellular processes.
 It isadirect sourceof energy for cell motility, muscle
contraction, and thespecific transport of substances
acrossmembranes.
 ATPisasourceof phosphateenergy for synthesisof the
other nucleosidetriphosphatesviathereaction:
ATPisalso an allosteric effector of many enzymes.

9. cytochromes:
Protein-bound :- Heme containing carriers
 Cytochromesconstituteafamily of
colored proteinscontaining the
Hemeprosthetic group

10. Nature of e- Carriers:
Protein-bound carriers :- Iron-sulphurcenters
 Feion iscoordinated with thesulphursof cysteine
residuesand inorgnic sulphur atoms.

11. Nature of e- Carriers:
Mobile carriers :- Coenzyme Q
 CoenzymeQ: small hydrophobic moleculeand theonly
onethat isnot apart of protein.

12. Organization of carriers in ETC:
Complex I
NADH dehydrogenase complex :
Largest Respiratory enzyme complex
> 40 polypeptide chains
Bound FMN
At least 7 iron-sulfur centers
Electron transfer From NADH to Co Q
Blocked by Rotenone and Amytal

13. Complex II
SuccinateDehydrogenase:
It isapoint of entry of electronsfrom FADH2
produced by theenzymesuccinatedehydrogenasein
thecitric acid cycle.
 FAD asProsthetic group
 Iron-sulfur proteins
 Electron transfer From FADH2 to Co Q
 Thus, both complexesI and II donatetheir electrons
to thesameacceptor, coenzymeQ.

14. CoenzymeQ :
 Benzoquinonelinked to 10 isopreneunits
 It hastheability to accept electronsin pairsand passthem one
at atimethrough asemiquinoneintermediateto Complex III.
Thiscycleisreferred to astheQ cycle.
 Electron transfer From Complex I or II to Complex III
Cytochromec : Thissmall mobileprotein accepts
e- from Complex III and shuttlesthem to Complex IV

15. Complex III
Cytochromeb-c1 complex :
It isaDimer
 Each monomer has:
3 Hemesbound to cytochromes
1 Iron-sulfur protein
 Electron transfer From Co Q to cytochromec
 Cytochromec then transferse- to thecomplex IV
 Blocked by Antimycin A

16. Complex IV
Cytochromeoxidasecomplex :
 Dimer
 Each monomer has:
13 Different polypeptidechains, including
2 Cytochromesaand a3 and
2 Cu atoms
 AcceptsoneElectron at atimefrom Cytochromec and
passesthem four at atimeto Oxygen
 Blocked by Cyanide, Azide, and Carbon monoxide

17. Organization of carriers in ETC:

18. Oxidative Phosphorylation
 Chemical coupling
 Chemiosmotic hypothesis
- proposed by Mitchel
- dependent on proton gradient.

20. Chemiosmotic Coupling:
 1. Theactivetransport of electronspumpsprotonsout of the
mitochondrial matrix into theinter membranespace.
 2. An electrochemical gradient of protonsiscreated, outsidethe
inner mitochondrial membranethan inside.
Theprotonson theoutsidehaveathermodynamic tendency to
flow back in.
 3. When protonsdo flow back into thematrix, thefreeenergy
arising from thegradient (21 kJ/mol of protons) is dissipated,
with someof it being used to drivetheATPsynthesis.

21. Chemiosmotic Coupling

22. ATP Synthase:
ATPsynthase or F0F1 complex or
Complex V
 Head F1
 Stalk F0

23. P:O Ratio
 TheP:O ratio refersto:
thenumber of Inorganic Phosphatemolecules
utilized for ATPgeneration for every atom of
Oxygen (apair of e-) consumed.
.

24. P:O Ratio
 Electronsentering thesystem at complex I from
NADH haveaP/O ratio of about 3/1.
 Electronsentering thesystem at complex II
FADH2'shaveaP/O ratio of about 2/1.

25. ATP Synthesis by ATP Synthase
 Boyer’sBinding ChangeMechanism

26. Inhibitors of ETC

27. Inhibitors of ETC:
 Bind to oneof thecomponentsof ETC and Block the
transport of Electrons.
 At Complex I: Rotenone, Amytal & Piericidin A
 Between cyt b and c1: Antimycin A & BAL
 At Complex IV: CO, Cyanide, Azide& H2S

28. Inhibitors of Oxidative Phosphorylation:
 Uncouplers: 2,4- DNP, FCCP(trifluoro carbonyl
cyanidephenyl hydrazone)
Thyroxin, FFA
Blocksbetween oxidation and phosphorylation
 Ionophores: Valinomycin, Nigercin
altersthepermeability of mitochondrial membrane

29. OtherInhibitors
 Oligomycin: ATPsynthase
 Atracyloside: Adeninenucleotide
carrier(Translocase)

34. Thank you