Many Proteins are Enzymes (AQA A Level Biology)

Enzymes as Proteins

• Enzymes are biological catalysts

  • ‘Biological’ because they function in living systems

  • ‘Catalysts’ because they speed up the rate of chemical reactions without being used up or changed

• Enzymes are also globular proteins

• Critical to the enzyme's function is the active site where the substrate binds

• Metabolic pathways are controlled by enzymes in a biochemical cascade of reactions

  • Virtually every metabolic reaction within living organisms is catalysed by an enzyme – enzymes are therefore essential for life to exist

• Enzymes can be intracellular or extracellular referring to whether they are active inside or outside the cell respectively

• Intracellular enzymes are produced and function inside the cell

• Extracellular enzymes are secreted by cells and catalyse reactions outside cells (eg. digestive enzymes in the gut)

Enzymes Table