4.2 Factors Affecting Enzyme
Activity
First review @November 17, 2023
Practise Q's Done
for enzymes to catalyse reactions, their active site must be complementary to the
substrate.
the shape of the active site can be affected by temperature and pH
if the shape of the active site changes, enzyme-substrate complexes cannot be formed and
so the rate of reaction decreases— this is called denaturing
Temperature
an increase in temperature of an environment increases the kinetic energy of the particles
— this means that the particles collide successfully more frequently and therefore rate of
reaction is increased
temperature coefficient (Q10)— a measure of how much a rate of reaction increases
with a 10 degrees Celsius increase in temperature
for enzyme controlled reactions the temperature coefficient is usually measure as
two— this means that the rate of reaction doubles as the temperature is increased by
10 degrees Celsius
Denaturation from temperature:
at higher temperatures, the bonds holding the enzyme proteins together begin to vibrate
more and as a result, they weaken and then break
when these bonds are broken, the tertiary structure of proteins changes and so the
active site changes— this means that the active site is no longer complimentary to
the substrate and so the enzyme can no longer function
when an enzyme changes shape it has denatured
Optimum temperature:
optimum temperature is the temperature at which the enzyme has highest rate of
activity
4.2 Factors Affecting Enzyme Activity 1
Activity
First review @November 17, 2023
Practise Q's Done
for enzymes to catalyse reactions, their active site must be complementary to the
substrate.
the shape of the active site can be affected by temperature and pH
if the shape of the active site changes, enzyme-substrate complexes cannot be formed and
so the rate of reaction decreases— this is called denaturing
Temperature
an increase in temperature of an environment increases the kinetic energy of the particles
— this means that the particles collide successfully more frequently and therefore rate of
reaction is increased
temperature coefficient (Q10)— a measure of how much a rate of reaction increases
with a 10 degrees Celsius increase in temperature
for enzyme controlled reactions the temperature coefficient is usually measure as
two— this means that the rate of reaction doubles as the temperature is increased by
10 degrees Celsius
Denaturation from temperature:
at higher temperatures, the bonds holding the enzyme proteins together begin to vibrate
more and as a result, they weaken and then break
when these bonds are broken, the tertiary structure of proteins changes and so the
active site changes— this means that the active site is no longer complimentary to
the substrate and so the enzyme can no longer function
when an enzyme changes shape it has denatured
Optimum temperature:
optimum temperature is the temperature at which the enzyme has highest rate of
activity
4.2 Factors Affecting Enzyme Activity 1
