immobilised enzymes Flashcards
what is an immobilised enzyme
an enzyme which is held in place and not free to diffuse through the solution
what protein is a enzyme
globular protein
what bond is used to join amino acids
peptide
what is an enzyme
biological catalyst which lowers activation energy of a reaction to speed it up
what are the advantages of immobilised enzymes not mixing freely with substrate
- enzymes become reuusable
- enzymes dont mix with product therefore they dont need to be extracted out of the product
- the immobilising matrix that surrounds the enzymes protects then from different conditions which can cause denaturation
what factors can denature an enzyme
high temp
wide ph range
what are the 3 methods to immobilise enzymes
adsorption
entrapment
covalent bonding
what is adsorption
enzymes make hydrophobic link and ionic bonds with a supporting surface, with active site accessible to substrate.
what are examples of supporting surfaces used in adsorption
insoluble
e.g. clay, glass beads, resins.
what are the disadvantages of immobilisign enzymes using adsorption
ionic bonds and hydrophobic links used in adsorption can be weak, causing enzyme to break and enter the reaction mixture.
what is the covalent bonding method
enzyme are bound to a supporting surface using Strong covalent bonds. such as crosslinks.
what are the disadvantages of a covalent bonding method used to immobilise enzymes
producing covalent bonds can be expensive
producing covalent bonds can also distort active sites and reduce the amount of es complex made.
comparing covalent bonding and adsorption. which method has a higher chance of enzymes leaking into reaction mixture
adsorption
because it has weaker links between enzyme and supporting surface.
what is entrapment
enzymes are trapped in a matrix that is partially permeable and doesnt allow free movement.
enzymes remain fully active.
substrate must diffuse into the entrapment matrix.
products can diffuse out of matrix.
what factors may affect entrapment
if substrate molecules are too large they may not be able to diffuse in the immobilised matrix
what is the main method to immobilise enzymes in entrapment
calcium alginate beads.
what must the membrane be in entrapment process
partially permeable
What is glucose isomerase
Converts glucose to fructose
Makes high fructose corn syrup HFCS used in diet foods and soft drinks
What is penicillin acylase
Makes semi synthetic penicilli
Used when bacteria is resistant to normal penicillin
What is lactase
Enzyme which converts lactose to glucose and galactose
Produce lactose free milk
People with lactose intolerance can still drink milk
What is aminoacylase
Hydrolase used to produce l amino acids by removing the acrylic group from
the nitrogen of a n amino acids
Can synthesis pharmaceutical products
What is glucoamylase
Converts dextrins to glucose
Used to digest starch
Enzyme used in wide range of fermentation processes
What is nitrile hydratase
Converts nitriles to amides
Forms polyacrylamide which can be used to treat water.
