PREPARED BY: MUHAMMAD ARIFF B. MAHDZUB BACHELOR MEDICINE AND SURGERY (MBBS) UNIVERSITY COLLEGE SHAHPUTRA, KUANTAN

1. 1
FACTOR AFFECTING ENZYME -
CATALYZED REACTION
PROBLEM BASED LEARNING (PBL)
PREPARED BY: MUHAMMAD ARIFF B. MAHDZUB
BACHELOR MEDICINE AND SURGERY (MBBS)
UNIVERSITY COLLEGE SHAHPUTRA, KUANTAN

2. FACTOR AFFECTING EMZYME -CATALYZED
REACTION

3. FACTOR AFFECTING ENZYME-
CATALYZED REACTION
CAN BE DIVIDED INTO TWO :
1. Due to frequency of collision
2. Due to energy barrier of reaction

4. FACTORS
FREQUENCY OF
COLLISIONS
SUBSTRAT
E
CONCENTR
ATION
COENZYME
CONCENTRATION
ENZYME
CONCENTRATION
ENERGY
BARRIER OF
REACTION
TEMPERATURE
MODIFIER
pH

5. FREQUENCY OF
COLLISION:• Substrate concentration
substrate concentration,
the rate of reactions.
This is because more substrate molecules will be
colliding with enzyme molecules, so more products
will be formed
However, after a certain concentration, any
increase will have no effect on the rate of reaction
The enzymes will effectively become saturated, and
will be working at their maximum possible rate.

6. • Enzyme concentration
enzyme concentration,
rate of reactions
As more active site of enzyme presence to be
bind by substrate
as more enzymes will be colliding with substrate
molecules.

7. • Coenzyme concentration
• coenzymes are organic molecules that are
required by certain enzymes to carry out
catalysis.
• They bind to the active site of the enzyme
and participate in catalysis but are not considered
substrates of the reaction
• coenzymes often function as intermediate
carriers of electrons, specific atoms or functional
groups that are transfered in the overall reaction.
An example of this would be the role of NAD in the
transfer of electrons in certain coupled oxidation
reduction reaction

9. ENERGY BARRIER OF
REACTION
• Temperature
Increasing temperature, increases the Kinetic
Energy that molecules possess , will also
increases the possibility ES complex formed
As temperature increases, more bonds,
especially the weaker Hydrogen and Ionic bonds,
will break.
Breaking bonds within the enzyme will cause the
Active Site to change shape.

10. • pH
Enzymes in different locations have different
optimum pH values since their environmental
conditions may be different
Small changes in pH above or below the
Optimum do not cause a permanent change to
the enzyme, since the bonds can be reformed
However, extreme changes in pH can cause
enzymes to denature and permanently loose
their function

12. • MODIFIER
Can be either :
1. Positive modifier (activator)
2. Negative modifier (inhibitor)
The negative modifier can be
classified as :
1. Irreversible reaction
2. Reversible reaction

13. IRREVERSIBLE
INHIBITOR• Irreversible inhibitors usually
covalently modify an enzyme, and
inhibition therefore not be
reversed.
• They do not function by
destroying protein structure but
by specifically altering the active
site of their target.
• This inhibitor also often contain
reactive functional groups

14. REVERSIBLE INHIBITOR
Can be either:
1.Competitive
2.Noncompetitive
3.Uncompetitive

15. COMPETITIVE
INHIBITOR
• Will compete with substrate to
bind at active site of the enzyme
• Thus, the substrate can not bind
to form ES complex, but EI
complex were formed
• Can be overcome by increasing
the substrate concentration

17. NONCOMPETITIVE INHIBITOR
• No structural similarity to the
substrate
• Substrate and inhibitor will not
compete to bind to the active
site of enzyme
• Will bind to the allosteric site of
the enzyme
• Can not overcome by increasing
the substrate concentration
• binds equally well to the
enzyme whether or not it has
already bound the substrate

19. UNCOMPETITIVE INHIBITOR
• Uncompetitive inhibition, also
known as anti-competitive
inhibition
• Takes place when an enzyme
inhibitor binds only to the
complex formed between the
enzyme and the substrate (the E-
S complex).
• It will not bind to the free
enzyme
• The inhibition is not overcome by
high substrate concentration.