ATP is the most important form of chemical energy in cells. It contains adenine, ribose, and three phosphate groups linked by phosphoric acid anhydride bonds. The active form is a complex of ATP with a magnesium ion. ATP is formed through substrate-level phosphorylation and oxidative phosphorylation. It provides energy for cellular work by hydrolysis of its phosphate bonds. Releasing one phosphate forms ADP, which is recycled to ATP in mitochondria. The high-energy phosphates in ATP allow it to directly donate phosphate groups, pyrophosphate, or its whole adenosine moiety to activate other molecules in biological reactions.

1. BY
VANA JAGAN MOHAN RAO M.S.Pharm, MED.CHEM
NIPER-KOLKATA
Asst.Professor, MIPER-KURNOOL
Email: jaganvana6@gmail.com

2. ATP
The nucleotide coenzyme adenosine
triphosphate (ATP) is the most important
form of chemical energy in all cells.

3. ATP- Structure
ATP is a nucleoside triphosphate containing adenine, ribose,
and three phosphate groups.

4. Phosphate residues in ATP Structure
• In ATP, a chain of three phosphate residues are
linked to the 5'-OH group of the nucleoside
adenosine .
• These phosphate residues are termed α, β, and γ.
• The α phosphate is bound to ribose by a
phosphoric acid ester bond.
• The linkages between the three phosphate
residues, on the other hand, involve much more
unstable phosphoric acid anhydride bonds.

6. Role of Mg++
• The active coenzyme is a complex of ATP with
an Mg2+ ion, which is co-ordinatively bound to
the β and γ phosphates (Mg2+ATP4–).

7. Mechanisms of ATP formation
There are two basic mechanism involved
for ATP formation-
Substrate level phosphorylation and
Oxidative phosphorylation

8. 1) Substrate level phosphorylation
• involves phosphorylation of ADP to form
ATP at the expense of the energy of the
parent substrate molecule without
involving the electron transport chain.
• Substrate is a high energy compound as
compared to the product, the surplus
energy is used for ATP formation.

9. Substrate level phosphorylation in Glycolysis
• Conversion of 1,3 BPG to 3, Phosphoglycerate

10. Substrate level phosphorylation in Glycolysis
• Conversion of phospho- enol -pyruvate
to Pyruvate

12. Substrate level phosphorylation in skeletal
muscle
Creatine phosphate, “energy-rich” phosphate compound is formed from ATP in muscle
It can regenerate ATP as needed.

13. 2) ATP by Oxidative phosphorylation
This process takes place in mitochondria and is energetically coupled to a
proton gradient over a membrane.
The H+gradients established by electron transport chain are used by the
enzyme ATP synthase as a source of energy for direct linking of an inorganic
phosphate to ADP.

15. Energy of hydrolysis
• Energy is usually liberated from the ATP
molecule to do work in the cell by a
reaction that removes one of the
phosphate-oxygen groups, leaving
adenosine diphosphate (ADP).
• When the ATP converts to ADP, the ATP is
said to be spent.
• Then the ADP is usually immediately
recycled in the mitochondria where it is
recharged and comes out again as ATP.

16. ATP Hydrolysis
Adenosine attachedto two or
one phosphate residues is
called Adenosine di and
mono phosphate respectively.
The symbol ~ indicates that
the group attached to the bond,
on transfer to an appropriate
acceptor,
results in transfer of the
larger quantity of free energy.
For this reason, the term group
transfer potential rather than
"high-energy bond" is preferred .

17. Status of AMP
• The phosphate in AMP (adenosine mono
phosphate) is of the low-energy type, since
it is a normal ester linkage.
• High AMP level depicts a low energy state
of a cell.

19. Examples of coupling reactions
ATP can donate
Single phosphate,
Two phosphatesor
 Even Adenosine moiety to suitableacceptors
for the formation of important biological
compounds.

20. A) Single phosphate transfer
The phosphorylation of glucose to glucose 6-phosphate, the first reaction of
Glycolysis, is highly endergonic and cannot proceed under physiologic conditions.
When (1) and (2) are coupled in a reaction catalyzed by hexokinase,
phosphorylation of glucose readily proceeds in a highly exergonic reaction that under
physiologic conditions is irreversible.

21. B) Transfer of two phosphate groups
During the process of
activation of fatty acid
before oxidation, ATP
is converted to AMP
with the release of
pyrophosphate, which
can subsequently be
hydrolyzed to
inorganic phosphates.
i) Activation of fatty acids

22. B) Transfer of two phosphate groups (contd.)
ii) Activation of amino acids-Amino acids are
activated before incorporation into the
growing peptide chain .

23. C) Transfer of adenosine moiety
This takes place during activation of Methionine to S-
Adenosyl Methionine (Active Methionine), which is a
methyl group donor in the body.

24. Fate of AMP
• AMP, formed as a consequence of several activating
reactions involving ATP, is recovered by
rephosphorylation to ADP.
• Adenylyl Kinase (Myokinase) interconverts Adenine
Nucleotides
• This enzyme is present in most cells. It
catalyzes the following reaction:

25. • The other nucleotides -GTP, CTP and UTP ,
do participate in metabolic reactions but
the ease with which ATP can donate single
phosphate, two phosphates, or even
Adenosine moiety is considered a better
nucleotide in energy transfer reactions .
ATP- The energy currency

26. Significance of other nucleotides
• GTP has a role in gluconeogenesis and in the
process of translation ; CTP is required for
phospholipid and triacylglycerol synthesis ,
while UTP is required for glycogen synthesis
and also in Uronic pathway for the synthesis
of glycosaminoglycans and for detoxification
reactions.

27. BY
VANA JAGAN MOHAN RAO M.S.Pharm, MED.CHEM
NIPER-KOLKATA
Asst.Professor, MIPER-KURNOOL
Email: jaganvana6@gmail.com

28. INTRODUCTION

29. BIOSYNTHESIS OF CREATINE

30. FORMATION OF CREATINE PHOSPHATE

31. DISTRIBUTION OF CREATINE

32. DEGRADATION OF CREATINE

33. CREATINE IN URINE AND PLASMA

34. ROLE OF CREATINE KINASE