This document discusses the effects of pH, substrate, and temperature on enzyme-catalyzed reactions. It explains that pH can alter the shape of the enzyme and substrate, preventing them from interacting. Each enzyme works best at its optimum pH. Higher substrate concentrations lead to more frequent collisions and higher reaction rates, up to saturation. Temperature initially increases reaction rate by providing more kinetic energy, but excessive heat can denature the enzyme permanently by altering its shape.

2. PRESENTED BY
MUHAMMAD
MUZAMILARSHAD

3. TOPIC
EFFECT OF pH, SUBSTRATE
AND TEMPERATURE ON
ENZYMES CATALYZED
REACTIONS

4. CONTENT
 ENZYMES
 EFFECT OF PH ON ENZYMES
 EFFECT OF SUBSTRATE ON ENZYMES
 EFFECT OF TEMPERATURE ON ENZYMES

5. QUESTION ARISES
What are enzymes?

6.  Enzymes are the biological catalyst
 Enzyme are proteins
 They increase the rate of reaction
 Each enzyme is specific to a substrate
 Enzymes are not used up in a reaction ,they
can be use over and over again

9. POINT TO REMEMBER
All enzymes are catalysts
but ……….
All catalysts are not
enzymes

10. Classification of enzyme

11. EFFECT OF pH ON
ENZYMES

12. Why pH affect enzymatic
activity?
 Alteration in the shape of the enzyme
 Alteration in the shape of substrate
 Substrate and enzyme don't recognize each
other so reaction does not occur
 So ,pH is the determining factor of enzymatic
activity

13. How pH affect enzymatic activity?
 Each and every enzyme is characterized by an
optimum pH . At this specific pH level, a particular
enzyme catalyzes the reaction at the fastest rate
than at any other pH level.
 For example, the enzyme pepsin is most active
at an acidic pH, whereas the enzyme trypsin
performs best at a slightly alkaline pH . Thus,
the optimum pH of an enzyme is different from
that of another enzyme.

15. EFFECT OF SUBSTRATE ON
ENZYMES
 Greater the substrate so greater is the rate of
reaction
 More substrate so there is more frequent
collision with enzyme
 So reaction rate is high all active side of
enzymes are occupied
 Saturation level

17. EFFECT OF TEMPERATURE
ON ENZYME
 a) If temperature is reduced to near or below
freezing point, enzymes are inactivated only, not
denatured
 b) As the temperature increase, the kinetic energy
of the substrate and enzyme molecules increases
and so they move faster. and the greater the rate
of reaction.
 c) As the temperature increases further, the
breakage of the hydrogen bonds and other strong
forces occurs

18.  So the shape of the active site altered and no
longer fit the substrate.
 The enzyme is said to be denatured and loses
its catalytic activity forever.