Enzymes

• Enzymes are proteins that are involved in all metabolic reactions, where they function as biological catalysts
• Enzymes are catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction
• Enzymes are necessary to all living organisms as they maintain reaction speeds of all metabolic reactions at a rate that can sustain life
• If enzymes were not produced, it would take around 2-3 weeks to digest one meal; with enzymes, it takes around 4 hours
• Enzymes and substrates randomly move about in solution
• When an enzyme and its complementary substrate collide, an enzyme-substrate complex forms, and the reaction occurs
• A product forms from the substrate(s) which are then released from the active site. The enzyme is unchanged and will go on to catalyze further reactions
• Enzymes are specific to one particular substrate as the active site of the enzyme is a complementary shape to the substrate
• Enzymes work fastest at their optimum temperature, which is 37⁰C in the human body
• Heating enzymes to high temperatures beyond the optimum will denature them, making them lose their shape irreversibly
• Increasing the temperature from 0⁰C to the optimum increases the activity of enzymes
• Low temperatures do not denature enzymes, they just make them work more slowly
• The optimum pH for most enzymes is 7, but some have different optimum pH levels based on where they are produced
• If the pH is too high or too low, the bonds holding the amino acid chain together can be destroyed, changing the shape of the active site