Study of effect of pH on Catalase enzyme activity.

Study of the effect of pH on Catalase enzyme activity.

Aim: Study of the effect of pH on Catalase enzyme activity.

Principle: The enzymes are the biological catalysts, increase the rate of biochemical reactions without taking part and work at certain pH, loose their activity at higher temperatures. They are protein in nature and remain unchanged at the end of the reactions.

STUDY OF ENZYME ACTIVITY – CATALASE. 

This enzyme is present in the peroxisomal microbodies which are found in the cell cytoplasm. Hydrogen peroxide present in the plant part/leaves is toxic to the plant which is broken down in to water and oxygen. The freed oxygen is received by the atmosphere which is further used by all the living organisms (aerobic).

The reaction can be shown as:-

2H2O2 + Catalase 2H2O +O2

(Substrate) + (Enzyme) water +Oxygen

Requirements: Potato tuber/ fresh leaves (any plant).test tube and test tube holder, spirit lamp,

morter and pestle (if leaves are used as enzyme source.), Hydrogen peroxide (20%), D. W.

blade/knife, cotton.

Procedure: 1) Potato tuber is taken and cut in to small slices/pieces with the knife/blade.

2) Two clean test tubes are taken and labeled as boiled and fresh. Few pieces of potato are

taken in both the test tubes with 2ml of D.W.

3) The test tube which is labeled as boiled is heated on the spirit lamp for 5 minutes and allowed to cool at room temperature.

4) About 2 ml of 2H2O2 (20%) is added to both the test tubes and plugged with cotton and

both the test tube are observed.

5) The test tube with boiled potato slices does not show the evolution of oxygen but the test

tube without boiling (fresh) shows the evolution of oxygen bubbles.

6) The observation can be made as shown in the observation table. Note- 5% extract of leaves prepared in water can be used after filtration through muslin cloth about 2 ml. in places of potato slices. 

The procedure is same as above (1-6) except for potato slices. The result appears same. 

Test tube	The reaction mixture in the Test tube	Observations	Result
Boiled	Boiled Potato slices    (few) + 2ml DW→Heat→Cool → add 2ml 2H2O2   (20%)	No Evolution of oxygen bubbles.	Absence of enzyme activity catalase
Fresh	Potato slices (few) +2mlDW →add 2ml 2H2O2 (20%)	Evolution of oxygen bubbles.	Presence of enzyme activity catalase

Conclusion-

The test tube containing boiled potato pieces does not show the evolution of oxygen bubbles because at higher temperature the enzymes become denatured