This document discusses competitive enzyme inhibition. It begins by defining enzymes and inhibitors, noting that inhibitors reduce the rate of enzymatic reactions by blocking the enzyme without destroying it. It then classifies inhibitors based on reversibility and competitiveness. Specifically, it explains that competitive inhibitors are reversible and compete with the substrate for binding at the active site of the enzyme. This reduces the effective concentration of substrate and lowers the reaction rate. The document provides examples of competitive inhibition kinetics and graphs to illustrate the effect on reaction rates.

1. Enzyme Inhibition
(Competitive Inhibition)
Presented by: Swapnil Agarwal
Haren Patel, Vikshit Patel,
Alok Priyadarshi, Purnima Singh,
Parth Bhatt, Lakshesh Jadav

2. Enzyme – Enzyme – Enzyme!!!!
What is it
????
Lets see……

3. Inhibitors
• Inhibitors are chemicals that reduce the rate
of enzymic reactions
• The are usually specific and they work at low
concentrations
• They block the enzyme but they do not usually
destroy it
• Many drugs and poisons are inhibitors of
enzymes in the nervous system

4. Enzyme Inhibitors
Enzyme inhibitors are molecules that reduce
the catalytic activity of enzymes. Reducing of
effective enzymatic activity or complete
blocking of enzyme may cause either
complete death of cell either modifications in
the pathways.
Appln: Drugs with cause complete inactivation
of enzymes from essential pathways will cause
cell death and therefore such drugs can be used
as an antibiotics.

5. Example:

6. Classification:
• Basis of Reversibility:
– Reversible
– Irreservisible
• Basis of Competitiveness:
– Competitive
– Un Competitive
– Mixed

7. Basis of Reversibility:
• Reversible
• Reversible inhibitors bind to enzyme with only non
covalent interactions.
• Reversible inhibitors do not perform any chemical
changes in enzyme or themselves and they are in
dynamic equilibrium with solution and can be removed
from enzyme completely by reducing inhibitor
concentration in solution.
• Reversible inhibition is often used as a self-regulated
process in living cells, when the substrate or product of
some enzymes acts as inhibitors for other enzymes.

8. Basis of Reversibility:
• Irreversible
• Irreversible inhibitors binds to enzyme via covalent
bonds and prevent enzyme from further performing of
catalytic acts.
• It is necessary to understand, that irreversible
inhibitors act on some selected group of enzymes, with
no effect on other enzymes and proteins.
• According to this classification it is impossible to
consider chemical or physical agents which inactivate
all enzymes and protein as an inhibitors.

9. Comparison:
Reversible Irreversible
Binds via non covalent Binds via covalent
interactions interactions
Do not perform any Inhibitor binds to the
chemical changes substrate and prevent
catalytic activity of
enzymes.
Can be reversed, as there Irreversibility due to strong
is no bonding between the covalent bonding.
inhibitor and substrate.

10. Basis of competitiveness:
• Competitive Inhibition
–As the name implies, compete with the
substrate for active site of the enzyme.
–Inhibitor is similar to natural
substrates.
–Most commonly occurred process.

12. Competitive – Uncompetitive!!!
What is it
????
Lets see……

13. Inhibition Kinetics:
Rate Law:
rp = kcat (E .S)

14. Rearranging:

16. Total Enzyme:

19. Lineweaver-Burk Plot

20. Misc:
• Video
• Allosteric Binding
•Case Study

21. Questions..??