Experiments on the effect of temperature on enzyme activity

Department of Physiology and Biochemistry, College of Plant Science and Technology, Heilongjiang Bayi Agricultural and Reclamation University, China

Operation method

Experiments on the effect of temperature on enzyme activity

Principle

Enzyme catalysis is strongly influenced by temperature. Within a certain temperature range, the thermal denaturation of the enzyme is not significant as the temperature increases, while the enzymatic reaction rate increases until it reaches a maximum value. Since the enzyme is a protein, too high a temperature will cause rapid denaturation of the enzyme, resulting in enzyme inactivation, therefore, the reaction rate reaches its maximum value, with the increase in temperature, the reaction rate decreases sharply, to completely stop the enzymatic reaction. The temperature at which the reaction rate reaches its maximum value is called the optimal temperature for enzyme action. The optimum temperature of most animal enzymes is 37~40℃, and the optimum temperature of plant enzymes is 50~60℃. In this experiment, amylase was used to act on starch at different temperatures, and the degree of enzymatic hydrolysis of starch was examined with iodine solution to illustrate the relationship between temperature and enzyme activity.

Move

I. Instruments and reagents:

1. Instruments: (1) graduated pipette: 1 ml × 2, 2 ml × 1; (2) test tubes: 3; (3) test tube rack; (4) thermostatic water bath: 3; (5) ice bath

2. Reagents:

(1) 1% starch solution (containing 0.3% NaCl): prepared as before.

(2) pH7.0 phosphate buffer: the same method as before.

(3) Iodine solution

II. Operating Procedure:

Take 3 test tubes and follow the table below:

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