Enzymes Flashcards
What are catalysts ?
Speeding up a reaction without being altered.
What are the two very important properties of enzymes ?
- High specificity for substrates
- High catalytic rate
What reactions do enzymes catalyse ?
Enzymes will only catalyse reactions that would occur naturally
How enzymes acts as catalysts ?
They reduce the activation energy of a reaction
What is the process of the enzyme reaction ?
- Binding to the enzyme stabilises the substrate in the Transition state
- This is the most unstable state for the substrate
- Enzyme thus acts to reduce the Activation energy.
How do enzymes interact with substrate ?
They interact chemically with the substrate
What does NAD(P) DO AS AN ENZYME COFACTOR ?
Acts as an electron carrier
- Used by several oxidoreductases.
What are three factors influencing enzyme activity ?
- ENVIRONMENT
- Temp
- pH
-INHIBITORS - Competitive
- Non-competitive
COVALENT MODIFICATION
How does pH affect enzyme activity ?
As pH changes so does the charge on amino acid
Charge is important for enzyme function thus an optimum
How does temperature affect enzyme activity ?
Temp increases chemical reaction same for enzymes
Eventually protein denature so activity is lost
What is the difference between Competitive and Non - competitive inhibitors ?
-COMPETITIVE - Inhibitor mimics substrate structure and competes for binding site
-NONCOMPETITIVE - Inhibitor changes binding site to prevent enzyme action
Whats an example of covalent modification ?
-Phosphorylation is a common example.
-Catalysed by a group of enzyme kinases.
- Phosphorylation can either activate or inhibit the enzyme.
