As the temperature
increases, both the
enzyme and the
substrate gain more
kinetic energy
This means they move
faster. As a result, they
are more likely to
collide, resulting in
more collisions in a set
amount of time.
The more they collide,
the more likely they
are to form
enzyme-substrate
complexes, up to a
point.
After this point (the
optimum), some weaker
bonds, such as hydrogen
and ionic bonds, that hold
the tertiary structure of
the active site together
may break.
As a result, the active
site changes shape so
the substrate is no
longer complementary.
This means the reaction
cannot proceed and the
enzyme is denatured.
pH
Hydrogen ions are
attracted to negatively
charged ions. Hydrogen
bonds and ionic bonds hold
the active site together.
Excess hydrogen ions interfere
with the bonds, resulting in
the active site changing shape.
This means that the number
of E-S complexes will be
decreased.
This will also mean that
the charges will be
altered on the active
site. The binding of
substrates molecules to
the active site will be
interfered with.
The number of
acidic or basic
R-groups affects
the optimum pH.
Enzyme
concentration
Cells are constantly
recycling old enzyme
molecules to avoid
harming the cell
More enzymes mean
more active sites are
available. Additionally,
there will be more
successful collisions
More collisions mean
more E-S complexes
forming, so rate of
reaction increases.
After the concentration
is increased further, the
reaction reaches the
maximum rate. The extra
enzyme molecules will
not have substrates free
to fit the active site.
To avoid this,
increase the
substrate
concentration.
Substrate
concentration
Without a substrate,
the enzyme-catalysed
reaction cannot
proceed.
As the concentration
of the substrate
increases, there are
more substrate
molecules.
This means more
E-S complexes can
be formed, and
more product
molecules.
After the concentration is
increased further, the
reaction reaches the
maximum rate. All of the
enzymes' active sites are
occupied with substrate
molecules.