Effects of temperature on enzyme function

Similar to catalysts, enzymes such as catalase are known to activate the rate of the metabolism in the living cells by reducing the activation energy of the reacting molecules. By composition, all enzymes contain catalytic RNA and protein molecules which account for the reasons why they are affected by the external conditions such as changes in Ph range, temperature, inhibitors and like. The analysis entails investigating five different experiment which is centered on examining the activity and properties of the enzyme catalase in different conditions. Further, the experimental data collected are used to relate to the recent pre-viewed researchers to determine the authenticity of the findings

 Introduction

 By composition, enzymes have catalytic properties which function to speed the rate of the metabolic chemical reactions which take place in the living cells. According to Nishimoto et al. (405), the primary function of the enzyme is to act directly on the substrate and convert it to the product. Catalase is an example of a naturally found enzyme found in both plants, animals, and bacteria. Enzyme catalase function to break down hydrogen peroxide (very toxic) produce in the living cells into water and oxygen as the harmless by-products (Cornish-Bowden 15). However, catalase is specific, in that it reacts with particular kind of the substrate.  Also, the enzyme is affected by the environmental factors such as level of acidity and basicity, temperature, substrate concentration, inhibitors, and enzyme concentration.

PART ONE

 Part (I): Decomposition of the Hydrogen Peroxide with Enzyme Catalase

Hypothesis:

As the surface area of the substrate become larger, the rate of the reaction increases

Procedure / Method

Ø 5ml of pH 7 of the hydrogen peroxide was put into two test tubes and observations made.

Ø I cm slice of the banana was cut and divided into equal pie wedge weighing into1gram each

Ø The two empty test tubes were labeled as W and D

Ø On the edge of the banana was dropped straight into test tube labeled W

Ø A different piece of the banana was diced and dropped into test D

Ø With the help of one colleague, one held the test tube and dropper while the other poured the hydrogen peroxide into the test tubes containing the banana separately while timing

Ø The stopper was held until it was sure that that the pressure was equilibrated    

Ø The hypothesis which was expected in each condition was hypothesized

Results

Oxygen gas collected (ml)

Banana

Whole (W)

0

1.5

2.5

3

3.3

3.5

4.3

Diced (D)

0

2.8

4.7

6

10.6

7.4

7.7

Interpretation of the Results

 From the results obtained in the experiment, the hypothesis was positively supported. Diced banana had larger surface area than the whole banana; therefore, the rate of the reaction increased with increase in the surface area of the reacting solids. Cornish-Bowden (13) reasons that as the surface areas become larger, the more it exposes an area of contact with the substrate to speeding up the rate of the reaction. In other, the increasing the surface area of the reacting molecules by smashing the banana increases the rate of collisions of the reactants which in turn increase the rate of reaction.

Descriptive Analysis of the Experiment

Part (II):  Effects of Temperature on Enzyme Function

  Procedure/Method

Ø The apparatus for the gas collection were filled up and placed on the bench

Ø 5 ml of Ph 7 of the hydrogen peroxide was put into the test tubes and marked as

a. 1 for iced

b. B   for boiling

c. 37 for 37 C water bath

d.  R for room condition

Ø 5 grams of the liver were addended correspondingly in each test tube.

Ø With the help of the colleagues, 5 ml f 7 pH of the hydrogen peroxide was addended in each test tube simultaneously.

Ø By use of the gas jar, the volume of the oxygen gas produced was recorded at the interval of one minute.

Hypothesis:

If the temperature of the substrate is maintained at the optimum condition, the rate of rate of reaction of the enzyme catalase is sustained at the optimal stability

Results

Amount of oxygen gas produced (ml)

Mean

A

Iced

0

0

0

0

0

0

0

0

B

Boling

0

0

0

0

0

0

0

0

C

Water Bath at 37

5

6.5

7

8.5

8.5

8.5

8.5

7.5

D

Room Temperature (25 

4

4.2

6.1

7.2

7.4

7.3

7.4

6.2

 Interpretation of the Results

The enzyme catalase has the optimal temperature (37°C) under which it functions at best.  According to Nishimoto et al. (406), the temperature influences both the cleavage of the hydrogen bond and the structure of the enzyme catalase itself. From the result, in both set A and B, there was no oxygen gas which produced. In the former low temperatures deactivated the active site of the enzyme which binds to the substrate. The former on the other hand had extremely high temperatures which denatured the protein nature of the enzyme catalase. Room temperature in the set-up C, the rate at which hydrogen peroxide was decomposed to produce oxygen gas was relatively lower than in set up C. The difference is explained by the fact at 37°C, it is the optimal temperatures for the enzyme catalase. Essentially, as the temperature rises towards optimum, the bonds for the hydrogen peroxide are loosened, making it easier for the enzyme to act on it, thus increasing the rate of the reaction.

Descriptive Analysis of the Experiment

Part (III): Is Catalase Reusable?

 Procedure/ Method

Ø Hydrogen peroxide in the test tube labeled R was poured into the clean test tube and marked UP.

Ø 5g of the pieces of the liver were weighed and dropped into the test tube labeled UP, and the reaction was observed

Ø Using a different test tube, 5ml of pH 7 of the hydrogen peroxide was poured into the test tube with used liver and reaction observed.

Hypothesis: The enzyme catalase is reusable if does not get denatured.

Results

Oxygen gas collected (ml)

Mean

Time

0 mins

1mins

2min s

3mins

4mins

5mins

6mins

Iced

0

4

7.2

9

12.6

15

17

9.26

Room

0

12

34

39

43.5

42.5

43

30.5

Interpretation of The Results

According to the results obtained, the hypothesis was supported. From the conventional definition of catalyst, it is visible that catalase which functions as the biologist catalyst was reusable (Iwase, 3081). In view to this, the results are in consent with the biological reasoning that the reacting substances changes but the enzyme remains unchanged. Therefore, it can be concluded that enzymes are reusable.

Descriptive Analysis of the Experiment

Part (IV):  Reaction Rate of The Iced Liver Returned To Room Temperature

 Procedure/ Method

Ø Hydrogen peroxide was poured into the test tube labeled 1

Ø The iced liver was returned to the room temperature

Ø The gas collection was filled up and set up

Ø 5ml of pH 7 of the hydrogen peroxide was poured into the test tube containing ice-liver at the room temperature

Ø Immediately, the stopper was secured, and timing was commenced simultaneously

Ø The oxygen produced was determined at a one-minute interval

Ø Oxygen which was collected in part two was gathered and recorded in the table to determine in which the experiment the rate of reaction was faster 

Hypothesis: The rate of the reaction will be faster at room temperature than at iced temperature levels.

Results

Oxygen gas collected (ml)

Time

0 mins

1mins

2min s

3mins

4mins

5mins

6mins

Iced

0

3

6.2

8

11.6

14

14

Room

0

10

32

34

40.5

42.5

44

Interpretation of The Results

The experimental data supported the proposition. From the results, it is visible that reaction rate of the iced liver is slower than the iced liver return to the room temperature. In essence, given that if the enzymes are not denatured at the iced temperature points, (Cornish-Bowden 14), the rate of reaction it will become faster at the room temperature which relatively closer to the optimal range of the enzyme catalase.

Descriptive Analysis of the Experiment

Part V:  Effects of Ph on Enzyme Activity

 Procedure/ Method

Ø The gas collection apparatus was filled

Ø 5ml of pH 3 and pH 10 of the hydrogen peroxide were poured into two different test tubes.

Ø 5 gm of the liver cubes were cut and placed at the bottom two empty slide labeled pH 3 and 10 respectively.

Ø To each test tube, a stopper was set ready following the pouring of the corresponding hydrogen peroxide into the test tubes containing cubes of liver catalase.

Ø The stopper was held until the pressure equilibrated

Ø The volume of the oxygen produced was recorded at the time interval of one minute.

Ø Data collected for the pH 7 was transferred here for the comparison purposes.

Ø Liver cube was dropped in each test tubes at the same time and timing commenced immediately.

Hypothesis:  The optimum pH for enzyme catalase will be 7, and probably very extreme level of basicity (pH 10) will denature the protein nature of the enzyme.

Results

Liver pH

Oxygen gas collected (ml)

Time

0 mins

1mins

2min s

3mins

4mins

5mins

6mins

3

0

9

14.5

20.8

24

27.5

23.5

7

0

8.8

15

18.5

21

23.7

26.7

10

0

0.5

0.5

0.5

0.5

0.5

0.5

Interpretation of the Results

 Change in the pH affects both the shape and properties of the substrates (Iwase 3081).  Extreme levels of the acidity or basicity in the reactions prevent the substrate from binding to the active sites of the enzyme or deter it from undergoing catalysis. From the experimental data, it is visible that reaction rate was fastest at the pH 7. This upholds the conventionally agreed knowledge that catalase functions best at that pH in its natural states. However, there were experimental errors in the first experiment involving the Liver with a pH 3. Ordinarily, it is expected that the rate of the reaction to be relatively slower than at pH 7. However, the similar knowledge holds at pH 10. In both extremes, they inactive the active sites of the enzymes which bind with the catalase.

Descriptive Analysis of the Experiment

 PART TWO

 Effects of the pH   on Enzymatic aActivity

 According to the research conducted by Nishimoto et al. (407) on the effects of pH levels on the rate of enzymatic activity, it was reported each enzyme is specific to points of acidity and basicity. This research found that the point where the enzyme functions at best in the reaction is regarded to be the optimum Ph point. In a different study, Sies (613) found that extremely high or low pH levels deactivate and denature the structure of the enzyme catalase. The similar laboratory results established that the level of acidity and basicity of the reactant affect the stability of the macromolecular proteins; hence each enzyme has the specific range of the pH values in which it is most active. In respect to this, catalase functions best at the optimal conditions, in which either extreme are denaturing in nature, due to the breakdown of the tertiary and secondary bonds of the hydrogen bonds. In a different study, Iwase et al. (3081) reported that changes in the pH values of the substrate affect the rate of enzyme catalase in two different ways. First, it influences the shape of the enzyme and secondly it changes the chemical properties of the substrate, in which it can either bind or not. Therefore, the study concluded that in general all enzymes with catalase included, have the optimum pH value in which they are most active.

            To conclude, from the experimental data observed in the analysis, it is apparent that the rate of the catalase enzyme is affected by several factors such pH values and temperature. However, the study also established that during the reaction, the enzyme functions as the catalyst, which was proven in the experiment which hypothesized that enzyme catalase is reusable. Importantly, all the hypotheses were confirmed to be true, which indicate the tests were done under stringent conditions to avoid errors.

Works Cited

Cornish-Bowden, Athel. Principles of enzyme kinetics. Elsevier, 2014

Fersht, Alan. Structure and mechanism in protein science: A Guide to enzyme catalysis and protein folding. Vol. 9. World Scientific, 2017.

Nishimoto, Takuto, et al. “Important role of catalase in the cellular response of the budding yeast

Iwase, Tadayuki, et al. ”A simple assay for measuring catalase activity: a visual approach.” Scientific reports 3 (2013): 3081.

Sies, Helmut. ”Hydrogen peroxide as a central redox signaling molecule in physiological oxidative stress: oxidative eustress.” Redox biology 11 (2017): 613-619.

Saccharomyces cerevisiae exposed to ionizing radiation.” Current microbiology 70.3 (2015): 404-407.

Winterbourn, Christine C. ”The biological chemistry of hydrogen peroxide.” Methods in enzymology. Vol. 528. Academic Press, 2013. 3-25.