Enzymes Flashcards
Why are enzymes needed?
- they are biological catalysts
- alternative pathway that has a lower activation energy
What is an enzyme-substrate complex?
Complementary substrate and enzyme bind together to produce products released from enzymes
What’s the Lock and Key theory?
Where complementary enzyme and substrate bind together but they have one specific shape that make them able to bind
What’s induced fit theory?
When substrate binds to the enzyme, the active site changes shape around the substrate
How does temperature effect enzyme activity?
Increasing temp can denature a protein.
This is because the molecules gain kinetic energy, so move around more.
This can break H-bonds in the 3D structure, so the protein loses it’s “fold”
How does pH effect enzyme activity?
Changing the pH can denature proteins.
This is because the ions in the acid/alkaline solution interacts with the ionic bonds.
This can break ionic bonds in the 3D structure, so the protein loses it’s “fold”
What’s the equation for the rate of reaction?
Rate = amout (m&v) per unit time
What’s a competitive inhibitor?
An inhibitor that fits in the active site of an enzyme and forms inhibitor complex and causes no reaction
What’s a noncompetitive inhibitor?
When the inhibitor binds to the allosteric site, this causes the active site to distort which makes the substrate no longer complimentary.
No reaction occurs.
What is an immobilised enzyme?
An enzyme stabilised on an intert support material.
(stabilised = pH & temp have less effect, intent = non-reactive, material = cellulose)
What are the advantages of immobilising enzymes?
- tolerate a wilder range of temperatures & pH
- enzymes are easily recovered so can be re-used
- several enzymes with different temps & pH optima can be used in sequences
- product is not contaminated
- can be easily added or removed, giving greater control over reaction
What is a biosensor?
A device that uses immobilised enzymes attached to a membrane to detect a biologically important substrate found in a complex structure.
They convert chemical signals into an electrical signal.
