Introduction

  • Enzymes are proteins that act as biocatalysts. (It is different from catalytic RNA molecules called ribozymes and DNA molecules called synthetic deoxyribozymes.)
  • Specific Substrate binding
  • Organisation of enzyme structure(or ES&EI complex) : Active site = Binding sites + Catalytic site




Mechanisms

Lock and key model

Induced fit model

Interaction Aspects

  • Proximity and orientation
  • Proton donors or acceptors
  • Electrostatic catalysis
  • Covalent catalysis
  • Metal ion catalysis
  • Bond strain
  • Quantum tunneling
  • Active enzyme




Cofactors

Apoenzyme(Apoprotein) + Cofactor = Holoenzyme

Metal

Coenzyme

  • Prosthetic groups




Thermodynamics

Recation Spontaneity

Gibbs Free Energy ($\Delta G = G_{product} - G_{reactant}$)

- $\Delta G < 0$ : Exergonic Reaction(Spontaneous Reaction)
- $\Delta G = 0$ : At Equilibrium
- $\Delta G > 0$ : Endogornic Reaction(Non-spontaneous Reaction)


Standard and Biological Gibbs Free Energy



  • Activation Energy




Kinetics

Michaelis–Menten kinetics




Inhibition

Irreversible Inhibition

Competitive Inhibition

Uncompetitive Inhibition

Non-competitive Inhibition

  • Allosteric inhibitors
  • Allosteric Effect
 

 

 


Reference
Related Articles
  1. EC1 Oxidoreductases
  2. EC2 Transferases
  3. EC3 Hydrolases
  4. EC4 Lyases
  5. EC5 Isomerases
  6. EC6 Ligases
  7. EC7 Translocases