Enzyme Kinetics I

Question 1

What is an enzyme?

Answer 1

• Protein macromolecule that catalyzes chemical rxns.
  
  • E.g. HMG CoA reductase in cholesterol synthesis
• Has binding pockets so that drugs can alter chemical rxns

Question 2

What are the characteristics of enzymes?

Answer 2

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1. Specificity
2. pH
3. Temperature
4. Cofactors
   - Metals
   - Coenzymes
5. Inhibition/Induced

Question 3

What does an enzyme do?

Answer 3

• Decreases activation energy

- Rep. by Arrhenius equation

Question 4

• How does enzymes operate?

Answer 4

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• Acid-base catalysis (H+) (Proton transfer)
• Covalent catalysis (Electron transfer)
• Metals ion catalysis (electrostatic catalysis) (Charge stabilisation)
• Proximity and orientation
• Transition state binding

Question 5

What are the types of acid-base catalysis?

Answer 5

• Acid catalysed ester hydrolysis (Acetic acid)
• Base catalysed ester hydrolysis (Acetate)
• RNAse A mechanism
  
  • Histidine 12 and 119 usage

Question 6

What is covalent catalysis?

Answer 6

• Electron transfer as a mean in catalysis