would not survive without enzymes, proteins which are nature's catalysts. They
are extremely efficient and highly selective. Click on the animation to see
how the active site of an enzyme
can accept only one out of a variety of substrates.
model of an enzyme
active site, and the active site occupied by substrate.
stages of an enzyme
reaction are summarised as
As the reaction proceeds there are subtle changes in shape.
are fragile, and very sensitive to changes in pH and temperature which cause
changes in shape. Click on the image to see the animated effect of pH changes.
may assist with catalysis. These are small organic molecules which can interact
with the substrate. Sometimes bound metal atoms play either a structural or
Is there a limit to the increase in rate achievable by enzymes? Yes, the
rate at which the products can diffuse away from the active site. In reality
few enzymes reach this limit.