1.4.1 Many Proteins are Enzymes

Key Characteristics of Enzymes:

• Specificity:
  • Each enzyme has a unique active site—a specific region where the substrate (reactant) binds.
  • The shape of the active site is complementary to the shape of its specific substrate(s), meaning each enzyme typically catalyses only one particular reaction. This is known as enzyme specificity.
• Catalytic Action:
  • Enzymes reduce the activation energy needed for a reaction to occur, making it easier for molecules to interact and react.
  • This is essential for biological processes, as reactions would otherwise proceed too slowly to sustain life.
• Reusability:
  • Enzymes are not used up in the reactions they catalyse; they can be reused multiple times, making them efficient and economical for cells.

The Importance of Enzymes:

• Enzymes play a critical role in metabolic pathways within cells, from digestion and respiration to DNA replication and protein synthesis.
• Without enzymes, many reactions would be too slow to support the necessary functions of cells and organisms. Enzymes are central to life's processes, and their specific structures and functions make them uniquely suited to their roles as catalysts in biological systems.