4.3 Enzyme Inhibitors
First review @November 18, 2023
Practise Q's Done
Control of metabolic activity within cells
different steps in reaction pathways are controlled by different enzymes
controlling the activity of these enzymes regulates the rate and quantity of product
formation
enzymes can be activated by cofactors and inactivated by inhibitors
inhibitors are molecules that prevent enzymes from catalysing reactions— there are two
types: competitive and non-competitive
Competitive inhibition
a molecule/ part of a molecule that has a similar shape to the substrate of a specific
enzyme fits into enzyme active site
this molecule then blocks the substrate from entering the active site, which prevents an
enzyme from catalysing a reaction
because the enzyme cannot carry out is function, it is said to be inhibited
substrate and inhibitor molecules found in a solution will compete with each other to
bind to active sites on enzymes that are trying to catalyse the reaction
this reduces the number of substrate molecules binding to active sites in a given time
and therefore slows down the rate of reaction
for this reason this type of inhibitor is called a competitive inhibitor
the degree of inhibition depends on the concentrations of substrate, inhibitor and
enzymes within a solution
most competitive inhibitors only temporarily block the substrate from binding to the
active site of an enzyme, however there are exceptions such as aspirin
4.3 Enzyme Inhibitors 1
First review @November 18, 2023
Practise Q's Done
Control of metabolic activity within cells
different steps in reaction pathways are controlled by different enzymes
controlling the activity of these enzymes regulates the rate and quantity of product
formation
enzymes can be activated by cofactors and inactivated by inhibitors
inhibitors are molecules that prevent enzymes from catalysing reactions— there are two
types: competitive and non-competitive
Competitive inhibition
a molecule/ part of a molecule that has a similar shape to the substrate of a specific
enzyme fits into enzyme active site
this molecule then blocks the substrate from entering the active site, which prevents an
enzyme from catalysing a reaction
because the enzyme cannot carry out is function, it is said to be inhibited
substrate and inhibitor molecules found in a solution will compete with each other to
bind to active sites on enzymes that are trying to catalyse the reaction
this reduces the number of substrate molecules binding to active sites in a given time
and therefore slows down the rate of reaction
for this reason this type of inhibitor is called a competitive inhibitor
the degree of inhibition depends on the concentrations of substrate, inhibitor and
enzymes within a solution
most competitive inhibitors only temporarily block the substrate from binding to the
active site of an enzyme, however there are exceptions such as aspirin
4.3 Enzyme Inhibitors 1
