Enzyme Flashcards
An enzyme is
biological protein catalyst that controls the rate of metabolism
It acts on a
substrate to produce a product
Amylase
starch to maltose
lactose acts on
lactose to glucose
Most enzymes are
3D folded globular proteins
All reactions are reversible
They are specific
meaning they will only act on 1 substrate
composed of
C, H, O and N. Sulphur may also be present
made up of
one or more polypeptide chains and formed on the ribosome
Denatured by
high temperature and unfavourable pH
How they work
join to the substrate molecule
this position they join is called the active site
Induced fit model
active site is not a fixed shape
when the substrate joins the enzyme it will change the shape of the active site
combine to form the enzyme-substrate complex
After the enzyme-substrate complex
the substance molecule reacts , the products are released and the unchanged enzyme is then available again
Factors affecting enzyme action
Temp
Ph
Enzyme concentration
Substrate concentration
Temp v rate of enzyme action
positive quadratic graph
pH v rate of enzyme action
two narrow quadratic graphs
Enzyme concentration v rate of enzyme action
linear graph
Substarte concentration
linear than plateaus
inhibitor
nerve gas
radiation
Bioprocessing
use of biological organisms to carry out manufacturing or treatment procedures of commercial or scientific interest
Bioreactor
sterile vessel in which organisms or their parts are used to make a product
Immobilised Enzyme
Enzymes attached to each other or to an inert material such as glass bead or sodium alginate gel
Advantages
Enzymes can be recycled , therefor the process is cheaper
efficiency of an enzyme is not affected
easy purification of the product
Experiment
Determine the effect of pH or temperature on enzyme activity
Enzyme = catalase (celery) Substrate = hydrogen peroxide product = water and oxygen
mix catalase, hydrogen peroxide, buffer and washing up liquid. Note the volume after 2 minutes
Control = no catalase
Experiment
examine application of immobilised enzymes
Enzyme = Sucrase Cell = yeast
Yeast is mixed with sodium alginate, Beads are syringed into a calcium chloride solution. The beads are filtered and allowed to harden
Immobilised sucrase is placed in a separation funnel and a solution of sucrose is allowed to pass through. Test the filtrate for glucose using clinstix
