An enzyme is a protein catalysts
that speeds up a reaction without
being used up in the reaction
Active site Theory of Enzyme Action
The active site of an enzyme is the
area where the substrate enters and is
changed into a product
Specificity refers to an enzyme's ability
to react with only one substrate
The lock and key model
Enzyme has a
rigid shape and
substrate fits
into active site
The Induced fit Model
The substrate(s) does not fit perfectly into
active site but the active site is flexible
Active site changes shape to fit substrate, enzymes
active site acts on substrate to convert it to a
product
Product is released and active site changes back to its original shape
Factors affecting Enzyme Action
Temperature
Above a certain temp. the enzyme
loses its shape and its ability to
function. It is said to be denatured
As the temp. rises, molecules move faster. This causes
enzymes and substrate molecules to collide more often. For
this reason the rate of enzyme reaction increases with temp.
It's optimum temperature 37 ºC
pH
Changes in pH disrupt
the enzyme's shape
If the enzyme's shape is lost, it
cannot act on its substrate
Bioprocessing
is the use of enzyme-controlled
reactions to make a product
Immobilised Enzymes
are enzymes that are attached to
each other or to an inert substance
Benefits
Immobilised enzymes can be reused
Product contains no enzyme (saves
on separation costs)
They are as efficient as isolated enzymes
Uses
Immobilised lactose breaks down lactose
in milk for lactose-tolerant people
Immobilised glucose isomerase is used in sweet
manufacture to convert glucose to fructose
A bioreactor is a vessel in which cells
or enzymes produce useful products