Enzymes

Enzymes

• Enzymes are biological catalysts as they have the organic substances needed to speed up reactions while remaining unchanged

Features

• They are made of protein

• They are very specific to their substrate

• They can join small molecules or break down large molecules

• They can do this with lower activation energy than if the enzyme was not used

• The substrate fits into the active site like ‘lock and key’ a hypothesis

• The induced fit model suggests the same idea of a lock and key hypothesis, except that the active site slightly changes to ensure a snug fit of the substrate.

Factors that affect rate of enzyme reaction

• Temperature

  • At low temperatures reaction is slow

  • An increase of 10° C doubles the rate of reaction

  • Every enzyme has a different optimum temperature - mammals 37-40° C

  • A slight increase about the optimum (usually up to 50°C will slow down the rate of reaction.

  • At high temperatures, the enzyme will be denatured and its active site will be permanently altered due to intense kinetic energy.

• Enzyme concentration

  • The more enzyme molecules there are the more active sites there are to act on the substrate molecules

  • Therefore an increase in enzyme concentration increases to rate of reaction

• Substrate concentration

  • The more substrate molecules there are the…