Enzyme Reactions and Temperature

Satisfactory Essays
Enzyme Reactions and Temperature


Aim - To determine the effect of temperature on the rate of reaction

of rennin when it reacts with milk to cause coagulation.

Hypothesis - As rennin is naturally found in the human stomach I

believe that the optimal temperature for reaction will be

approximately 37°C as this is the regular human body temperature. This

is shown by the graph below.


Background Research

Rennin is "an enzyme that catalyses the coagulation of milk, found in

the gastric juice of the fourth stomach of young ruminants and used in

making cheeses and junkets. Also called chymosin, rennet."[2] It is

also found in the gastric juices, or Gastric mucosa, of many other

mammals, including humans. In the human stomach, particularly those of

infants, rennin works to curdle milk so that pepsin, another stomach

enzyme, can further breakdown the proteins into absorbable amino acids

called polypeptides

Several experiments have already been conducted testing similar

hypothesis and having similar aims. All of these experiments had very

similar results. They found that approximately 37°C was the optimal

temperature for rennin, it was at this temperature that the milk

solidified quickest. Below that the reaction would occur far more

slowly, sometimes taking hours to complete, sometimes not reacting at

all. Above 37°C at approximately 45°C the enzyme would become

denatured, and the reaction would never occur, even after the

temperature was lowered back down to 37°C.

Name of enzyme - Rennin

Name of substrate - Milk


- 50ml of full cream milk.

- 10 small test tubes.

- 5 140ml beakers.

- Access to both hot and cold water supplies.

- Pipettes.

- Junket tablets.

- Mortar and Pestle.

- Distilled water.

- Stopwatch.

- Thermometer.



-Using a pipette add 5ml of milk to each of the 10 small test tubes.

Label 5 controls and 5 variables.

-Place 100ml of water into each of the beakers, and using hot and cold
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