Enzymes: Overview and Mechanisms

Importance of Enzymes

• Enzymes are crucial for living cells to carry out numerous chemical reactions every second.
• Most chemical reactions are slow without assistance.

Challenges with Temperature Increase

• Raising temperature can speed up reactions but has several drawbacks:
  • Requires a lot of energy to maintain high temperatures.
  • High temperatures can damage cells.
  • Can accelerate unwanted reactions.

Definition of Catalysts

• Catalyst: A substance that increases the speed of a chemical reaction without being altered or consumed.
• Catalysts can be reused multiple times.
• Enzymes: A specific type of catalyst produced by living organisms, often referred to as biological catalysts.

Structure of Enzymes

• Enzymes are large proteins composed of long chains of amino acids.
• The specific sequence of amino acids determines their unique shape and function as enzymes.

Mechanism of Enzyme Action

• Enzymes speed up reactions involving substrates (reactants) to form products.
• Active Site: A unique region on the enzyme that is complementary in shape to the substrate.
  • If the substrate does not fit into the active site, the reaction will not be catalyzed.
  • Enzymes are highly specific for their substrates.

Models of Enzyme Action

1. Lock and Key Model:

   • Initially believed that substrates must fit perfectly into the enzyme's active site (like a key in a lock).

2. Induced Fit Model:

   • The enzyme adjusts its shape slightly when it binds to the substrate to enhance the fit (like a hand fitting into a rubber glove).
   • Emphasizes that the active site is complementary to the substrate but allows for some flexibility.

Additional Resources

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