Enzymes
Enzymes are biological catalysts which speed up chemical reactions without being used up or
changed. They are globular proteins where the enzymes function is critical to its active site
which it where the substrate binds.
The active site is usually a hollow in the globular structure where the substrate can bond to the
amino acid side chains through a variety of interactions: hydrogen, van der waals, permanent
dipole-dipole and ionic bonding.
The interactions need to be strong enough to hold the substrate for long enough for the
enzyme catalysed reaction to occur - but weak enough so that the product can be released.
The 'Lock and Key Model' is used to explain the specificity of an enzyme.
The active sites of enzymes are stereospecific as they only work on one enantiomer of a
substrate. If the substrate is chiral the other enantiomer would not fit and no enzyme-substrate
complexes would be formed.
Inhibitors and Drugs
Drugs bind to receptors using intermolecular forces or ionic bonds. The stronger the interaction
the more effective the drug activity is.
For example, bacterial cells are surrounded by a cell wall made of a murein. The antibiotic
penicillin inhibits the enzymes that produce the cross-links destroying the polymer chains. The
cell wall bursts causing the bacteria to be destroyed.
Enzymes are biological catalysts which speed up chemical reactions without being used up or
changed. They are globular proteins where the enzymes function is critical to its active site
which it where the substrate binds.
The active site is usually a hollow in the globular structure where the substrate can bond to the
amino acid side chains through a variety of interactions: hydrogen, van der waals, permanent
dipole-dipole and ionic bonding.
The interactions need to be strong enough to hold the substrate for long enough for the
enzyme catalysed reaction to occur - but weak enough so that the product can be released.
The 'Lock and Key Model' is used to explain the specificity of an enzyme.
The active sites of enzymes are stereospecific as they only work on one enantiomer of a
substrate. If the substrate is chiral the other enantiomer would not fit and no enzyme-substrate
complexes would be formed.
Inhibitors and Drugs
Drugs bind to receptors using intermolecular forces or ionic bonds. The stronger the interaction
the more effective the drug activity is.
For example, bacterial cells are surrounded by a cell wall made of a murein. The antibiotic
penicillin inhibits the enzymes that produce the cross-links destroying the polymer chains. The
cell wall bursts causing the bacteria to be destroyed.
