The effect of temperature on an enzyme
Information
Rennin is an enzyme that acts on the milk protein casein causing it to set (clot and form a curd). This has the effect of keeping liquid food in the stomach long enough do that some digestion can take place.
Rennin is found in the stomachs of babies and young children whose diet is mainly milk.
Method
Materials
Risk analysis
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Procedure
Prepare half-filled water baths in styrofoam cups with an appropriate mixture of tap water, boiling water and ice for your allocated temperature. For 70
0
C and 80
0
C place water in 250 mL beakers over a Bunsen and adjust with cold water as necessary.
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* Use a measuring cylinder to place 3 ml of milk into a testtube. Place the testtube in the water bath and allow 10 minutes to reach a stable temperature.
Place 3 drops of prepared junket (rennin) solution into the testtube. Shake each testtube to mix then replace in the water bath.
Examine the testtube every minute for 20 minutes by tilting it gently, NOT shaking it. Record the time in a table each minute for 20 minutes that it takes the milk to clot. If no clotting occurs in 20 minutes stop.
Collate the results for the whole class, then graph them to analyse them.
Results
Temperature Clotting time Activity (1/Clotting time)