Question

In: Chemistry

Experiment IV: Effect of pH on the Rate of Enzyme Reaction 6. In this experiment, was...

Experiment IV: Effect of pH on the Rate of Enzyme Reaction

6. In this experiment, was the enzyme denatured or just slowed down at any of the pH values tested? What is the evidence?

Materials for Experiment IV

Five test tubes

Test tube rack

Disposable pipettes

Potato extract

Deionized water

Water bath, 37 degrees Celsius (°C)

0.1 molar (M) sodium hydroxide (NaOH)

0.1 M hydrochloric acid (HCl)

pH paper

Procedure for Experiment IV

Five test tubes were taken and labeled A to E.

According to table 7.4, drops of 0.1 M hydrochloric acid (HCI), 0.1 molar (M) sodium hydroxide (NaOH), and deionized water were added to five test tubes.

Table 7.4

Labeled

Amount of HCI

Amount of NaOH

Amount of Deionized Water

A

20 drops

0 drops

0 drops

B

1 drop

0 drops

19 drops

C

0 drops

0 drops

20 drops

D

0 drops

1 drop

19 drops

E

0 drops

20 drops

0 drops

The pH for each of the five test tubes using pH paper was recorded.

Later, 2 mL deionized water, eight drops of catechol, and eight drops of the potato extract were added into all five test tubes.

Each test tube was carefully mixed and placed into a 37 °C water bath.

After 15 minutes, a change of color was supposed to happen and had to be rated on a scale of 1–10 with 10 being the darkest.

The data was recorded in Table 4 of the Enzyme Lab Worksheet and presented to the class.

Solutions

Expert Solution

Catechol is oxidized by catechol oxidase enzyme to form benzoquinone, which, on exposure to air, forms melanin.

Optimum pH for the catechol oxidase reaction is 7. At pH 7, the enzyme is most active and rapidly catalyzes the oxidation of catechol to give the dark, brown color.

pH above or below will hinder the enzyme in its reaction .

Labeled

Amount of HCI

Amount of NaOH

Amount of Deionized Water

Effect on the reaction

A

20 drops

0 drops

0 drops

highly acidic media

colour change will not occur

enzyme denature

B

1 drop

0 drops

19 drops

slightly acidic media

colour change will happen but less

enzyme slightly denatured

C

0 drops

0 drops

20 drops

neutral media colour change will be highest

darkest in colour

D

0 drops

1 drop

19 drops

slightly basic

colour change will occur though less

enzyme slightly denatured

E

0 drops

20 drops

0 drops

highly basic

colour change will not occur

enzyme denatured

These enzymes  become denatured (lose their shape) if they are placed with a pH outside of its optimal range


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