Learning Intention: Students will better understand the use of mass spectroscopy in the diagnosis of a medical condition and explore the implications of enzyme deficiencies in protein metabolism. They will also understand the effect of pH on enzyme activity and apply their knowledge of scientific method to writing the procedure for a practical experiment.

Success criteria: Students will complete the practical activity “Absent enzymes – phenyketonuria and albinism”.

• Liver contains an enzyme that catalyses the reaction to breakdown hydrogen peroxide (H₂O₂)
• Enzyme activity in this case  is indicated by the production of oxygen – a splint re-ignites in the presence of oxygen.
• High temperatures denature proteins and prevent enzyme activity.
• Diastase in an enzyme in plants that converts starch into glucose at an optimum temperature of 20 degrees Celcius.
• The presence of starch in solution is indicated by iodine turning blue-black.

Your task is to devise an experiment that demonstrates the effect of pH on enzyme activity. Remember that pH is a logarithmic scale – a pH of 4 is ten times more H+ ions than a pH of 5.
pH and Enzymes
Effect of pH on enzyme activity

Second-hand data activity: PKU Genetics (YouTube, 5.00min)