Factors Affecting Enzyme Activity

Warittha (Mint)Palita (Preem)Peeraya (Sui)

Punyawee (Earl)Punyathip (Ping)

Members:

Objective

To check how pH influences the color of the red cabbage extract indicator.

To investigate the effect of urease from soya beans on urea

To see the effect of ionic condition on urease.

Materials and Equipment

Red cabbage indicator5%, 10%, 20% solution of fertilizer urea10% solution of sodium bicarbonate10% citric acid solutionSoya bean extract ( Urease enzyme )Distilled water5%, 10%, Saturated salt(NaCl) solutionNaClPipette and Pipette gunTimerTest tubesTest tube rackVortex

Introduction

UreaseAn enzyme that catalyzes the hydrolysis of urea to ammonia and carbon.

Red cabbage extract

In this experiment, red cabbage extract acted as a pH indicator. We used it to identify ammonia which is a product of the hydrolysis of urea.

CO(NH ) + H O 2NH + CO 222 32

A basic compound that change the color of the indicator into green or blue

Procedure 1

• Pour 3ml of red cabbage extract into each test tubes.

• Add 2 drops of citric acid into test tube A• Add 2 drops of sodium bicarbonate into test tube B• Add 2 drops of distilled water into test tube C

Acidic

Neutral

Basic

Analyzing Result

Why is it important to have the three reference tubes?

Because we can use them to compare with

the other results and it’s easier to see. These three reference tubes are where we will refer whether the other result is acidic, basic or neutral.

Can you predict what color of the solution will be if the urease enzyme convert urea to ammonia?

Of course, we predict that when the urease

enzyme convert urea to ammonia will give out the green or blue color. Because ammonia is basic compound. According to the result of the first procedure, The green and blue color will be produced when base reacts with the indicator.

Procedure 2

• Add 2 ml of red cabbage indicator to each of three new test tubes ( A, B, C)

• Add 2ml of urea solution into test tube A and B• Add 2ml of distilled water into test tube C• Add 2 ml of the soya suspension into test tube B and C

SUMMARY :

TEST TUBE A : INDICATOR + UREA SOLUTION(10%)

TEST TUBE B: INDICATOR + UREA SOLUTION(5%) + UREASE

TEST TUBE C: INDICATOR + H O + UREASE2

A

CB

Analyzing Result

• What are the purpose of the procedure?

The purpose is to see that urea solution will only react with the test tube that contains soya suspension (urease) so that means to ensure that only urease that can react with urea solution and give out ammonia.

• Why do we need to add an enzyme into a test tube without urea even though we can predict that no enzyme activity will occur?

We want to ensure that there’s no enzyme activity occur or it gave us the different color (pink) with the one that had enzyme activity occur. Which means it helps us conclude and make sure that enzyme activity only occur on the test tube B.

Procedure : Ionic concentration

• Add 2ml of soya suspension to each of the 3 test tubes.

• Add 2ml of 5% NaCl solution in test tube A• 2ml of 10% NaCl solution to test tube B• 2ml of saturated NaCl solution to test tube C• Add 2ml of 10% urea solution to all tubes• Add 2ml of red cabbage indicator to all tubes• Observe the color change for approximately 3

minutes

Our prediction

• We knew that we have to use the right amount of NaCl concentration in order to make that enzyme activity occur. We predicted that 5% NaCl will give that fastest reaction. And the SAT NaCl concentration will be too much.

SUMMARY:

TEST TUBE A: 5% NaCl + UREASE + 10% Urea solution + indicator

TEST TUBE B: 10% NaCl + UREASE + 10% Urea solution + indicator

TEST TUBE C: SAT NaCl + UREASE + 10% Urea solution + indicator

Time used: Sat NaCl > 10% NaCl > 5% NaCl

Analyzing Result

How does ionic condition affect the urease activity? How do you know?

Ionic condition affects the urease activity by changing the chemical molecule or makes the enzyme change their structure. If the enzyme changes their shape the reaction will not happen. We know by observe from the result of this experiment. If there is 5% NaCl solution in test tube it will take 1 minute to make the reaction happen. If there is 10% NaCl solution it will be more concentration and the reaction will happen slower than 5% NaCl solution. Moreover if people add saturated NaCl to the test tube that have urea, urease and indicator the reaction will happen slowest.

From your results, what ionic condition would you use and avoid if you have to conduct an experiment using urease enzyme and why?

In order to conduct an experiment, we should use the right amount of NaCl. According to the result of this experiment, we might use 5% NaCl solution instead of using other concentrations because we think that the right amount of NaCl that we should use for urease enzyme is 5% NaCl.

Conclusion

• Ionic concentration : enzyme works with in a right amount of salt concentration.

• What we predicted is correct!!

THANK YOU