83 WJEC Biology AS Level - Marianne Izen - 2nd Edition (1.4 Enzymes And Biological Reactions) Flashcards
What are the advantages of immobilised enzymes?
Increased stability and function over a wider range of temperature and pH than enzymes free in solution.
Products are not contaminated with the enzyme.
Enzymes are easily recovered for reuse.
A sequence of columns can be used so several enzymes with differing pH or temperature optima can be used in one process.
Enzymes can be easily added or removed, giving greater control over the reaction.
What are the uses of immobilised enzymes?
- Lactose-free milk
- Biosensors
- High-fructose corn syrup (HFCS) manufacture
Describe how immobilised enzymes are used for making lactase?
An important industrial use of immobilised enzymes is in making lactose-reduced or lactose-free milk.
The milk is passed down a column containing immobilised lactase.
The lactose binds to the active sites on the lactase and is hydrolysed into its components, glucose and galactose.
Describe the principles of use of immobilised enzymes in biosensors.
A major use of immobilised enzymes is in biosensors, which turn a chemical signal into an electrical signal.
Biosensors rapidly and accurately detect, identify and measure even very low concentrations of important molecules.
They work on the principle that enzymes are specific and are able to select one type of molecule from a mixture, even at very low concentrations.
Describe the use of biosensors in the detection of blood glucose.
One particular use of a biosensor is in the detection of blood glucose.
The enzyme glucose oxidase, immobilised on a selectively permeable membrane placed in a blood sample, binds glucose.
This produces a small electric current, detected by the electrode and read on a screen.
Enzymes can also be immobilised onto test strips, where different strips may detect a variety of molecules.
Testing strips with glucose oxidase immobilised onto them are used for detecting glucose in urine.
Describe the use of immobilised enzymes in the manufacture of high fructose corn syrup
What is important to remember when making a control for an experiment using algae or enzymes immobilised in alginate beads.
An experiment may use algae or enzymes immobilised in alginate beads.
To make a control, the algae or enzymes should be boiled and cooled before using them to make beads.
If you try to boll the beads, they will melt.
