The Effect of pH on Enzyme Activity


Length: 602 words (1.7 double-spaced pages)
Rating: Excellent
Open Document
Need writing help? Check your paper »

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Text Preview

More ↓
The Effect of pH on Enzyme Activity

pH is a measure of the concentration of hydrogen ions in a solution.
The higher the hydrogen ion concentration, the lower the pH. Most
enzymes function efficiently over a narrow pH range. A change in pH
above or below this range reduces the rate of enzyme reaction
considerably.

Changes in pH lead to the breaking of the ionic bonds that hold the
tertiary structure of the enzyme in place. The enzyme begins to lose
its functional shape, particularly the shape of the active site, such
that the substrate will no longer fit into it, the enzyme is said to
be denatured. Also changes in pH affect the charges on the amino acids
within the active site such that the enzyme will not be able to form
an enzyme-substrate complex.

The pH at which an enzyme catalyses a reaction at the maximum rate is
called the optimum pH. This can vary considerably from pH 2 for pepsin
to pH 9 for pancreatic lipase.



Results
=======

pH

1

2

3

Average

Rate of Reaction (cm3/s)

3

0

0

0

0

0.000

5

0

0

0

0

0.000

7

63

106

55

74.7

1.245

9

70

135

90

98.3

1.638

11

85

135

70

96.8

1.613

[IMAGE][IMAGE]



Conclusion
==========

From looking at the results I can conclude that when the pH was 3 and
5 no oxygen was produced, therefore no reactions were taking place.
This was because the pH had a high hydrogen ion content, which caused
the breaking of the ionic bonds that hold the tertiary structure of
the enzyme in place. The enzyme lost its functional shape,
particularly the shape of the active site, such that the substrate no

Need Writing Help?

Get feedback on grammar, clarity, concision and logic instantly.

Check your paper »

How to Cite this Page

MLA Citation:
"The Effect of pH on Enzyme Activity." 123HelpMe.com. 15 Dec 2017
    <http://www.123HelpMe.com/view.asp?id=121162>.
Title Length Color Rating  
The Effect of Temperature on Enzyme Activity Essay - The Effect of Temperature on Enzyme Activity Experiment: To investigate the effect of temperature on enzyme activity. The enzyme used will be catalyse. The enzyme catalyse: The enzyme catalyse is a biological enzyme. It is used to break down Hydrogen Peroxide, which is harmful. The reaction that occurs is: [IMAGE] Hydrogen peroxide Water + Oxygen The activity of the enzyme catalyse can therefore be measured by the amount of oxygen (in the form of froth) that is produced....   [tags: Papers] 1496 words
(4.3 pages)
Strong Essays [preview]
The Effect of pH on Enzyme Activity Essay - The Effect of pH on Enzyme Activity pH is a measure of the concentration of hydrogen ions in a solution. The higher the hydrogen ion concentration, the lower the pH. Most enzymes function efficiently over a narrow pH range. A change in pH above or below this range reduces the rate of enzyme reaction considerably. Changes in pH lead to the breaking of the ionic bonds that hold the tertiary structure of the enzyme in place. The enzyme begins to lose its functional shape, particularly the shape of the active site, such that the substrate will no longer fit into it, the enzyme is said to be denatured....   [tags: Papers] 602 words
(1.7 pages)
Strong Essays [preview]
The Effect of Temperature on the Rate of Enzyme Activity Essay examples - ... The first way is by helping the substrates to bind together. It is easier for substrates to react if they are closer together, thus bringing on the transition state. The second way is by repositioning them. Substrates do not travel in a particular direction and so if they are repositioned so that they collide, they will react. Another way to cause reactions is using an induced-fit model. This means that the enzyme changes its shape to better fit the substrate and make for a stronger bond. Finally stopping water molecules from getting through and disrupting the reactions will help binding occur....   [tags: biochemical analysis] 565 words
(1.6 pages)
Strong Essays [preview]
The Effect Of Substrate Concentration On The Activity Of The Enzyme Catalase - The Effect Of Substrate Concentration On The Activity Of The Enzyme Catalase A Level Biology Project Aims This is an experiment to examine how the concentration of the substrate hydrogen peroxide affects the rate of reaction of the enzyme catalase. Introduction This is a real A-level school project and as such is intended for educational or research purposes only. Extracts of this project must not be included in any projects that you submit for marking. Doing this could lead to being disqualified from all the subjects that you are taking....   [tags: biology experiment, chemistry experiment] 2003 words
(5.7 pages)
Powerful Essays [preview]
The Effect of pH on the Activity of the Enzyme Amylase Essay - The Effect of pH on the Activity of the Enzyme Amylase Aim :- To find the effect of pH on the activity of the enzyme amylase. An enzyme is a type of protein found in all living cells. Enzymes act as biological catalysts, breaking down substrates without needing a high temperature, allowing all the chemical reactions of metabolism to take place, regulating the speed at which they progress, lowering the activation energy and providing a means of controlling individual biochemical pathways....   [tags: Papers] 1088 words
(3.1 pages)
Strong Essays [preview]
Essay on The Effect of Temperature on the Activity of the Enzyme Catalase - The Effect of Temperature on the Activity of the Enzyme Catalase Introduction: The catalase is added to hydrogen peroxide (H²0²), a vigorous reaction occurs and oxygen gas is evolved. This experiment investigates the effect of temperature on the rate at which the enzyme works by measuring the amount of oxygen evolved over a period of time. The experiment was carried out varying the temperature and recording the results. It was then repeated but we removed the catalase (potato) and added Lead Nitrate in its place, we again tested this experiment at two different temperatures and recorded the results....   [tags: Papers] 1594 words
(4.6 pages)
Strong Essays [preview]
Investigation to Determine the Effect of Temperature on the Activity of the Enzyme Amylase - Investigation to Determine the Effect of Temperature on the Activity of the Enzyme Amylase I am trying to find out if changing temperatures affects the activity of enzymes. The Input variable I will test is temperature; the range I will use for this is 0-80°C. The out come variable to be measured is the speed of the reaction. Hypothesis I believe that at a higher temperature the enzyme will react quicker, but at a certain temperature the enzyme it will stop working. I think this because enzymes work well at higher temperatures because particles have more energy resulting in more successful collisions between them and a quicker reaction....   [tags: Papers] 616 words
(1.8 pages)
Strong Essays [preview]
The Effect of Substrate Concentration on the Rate of Activity of the Enzyme Catalase - The Effect of Substrate Concentration on the Rate of Activity of the Enzyme Catalase Background Information: Enzymes are biological catalysts that increase the speed of chemical reactions without undergoing any physical change. They are neither used up in the reaction nor do they appear as reaction products. All enzyme catalysed reactions are reversible. Enzymes effectively lower the amount of activation energy required for chemical reactions to start. Some enzymes weaken covalent bonds within the substrate molecule, whereas in other cases this lowering of the activation energy seems to take place because the enzyme holds the substrate molecules in a particular p...   [tags: Papers] 3145 words
(9 pages)
Powerful Essays [preview]
Enzyme Activity in the Catalase Essay - The purpose of this experiment was to see if there would be enzyme activity that is in catalase, which is found in potatoes. How my partner and me did the experiment was very simple, we put the filter paper filled with catalase concentration in to five sets of hydrogen peroxide. We found that the more concentration of hydrogen peroxide there was the faster it would take for the filter paper to reach the top, and the lower to no concentration level of hydrogen peroxide was the slower it would go to reach the top....   [tags: catalyst, potatoes, experiment] 1803 words
(5.2 pages)
Better Essays [preview]
The Effects of Enzyme Concentration on the Activity of Amylase Essay - The Effects of Enzyme Concentration on the Activity of Amylase To investigate the effect of Amylase concentration on its activity. the relative activity of Amylase is found by noting the time taken for the starch substrate to be broken down, that is, when it is no longer gives a blue-black colour when tested with iodine solution. This time is referred to as the achromatic point. Equipment: v Amylase solution 0.1% v Starch Solution 1.0% v Distilled water v Iodine in potassium iodine solution v White tile and polythene pipette v Graduate pipettes or syringes v Test tubes in rack v Beaker (used as water bath) v Stopwatch, Thermometer v Eye P...   [tags: Papers] 986 words
(2.8 pages)
Good Essays [preview]

Related Searches




longer fit into it, the enzyme is denatured. The ions also effected
the charges on the amino acids within the active site such that the
enzyme was unable to form an enzyme-substrate complex. Between 5 and 7
the amount of oxygen produced increased and therefore the amount of
reactions taking place was increasing as the pH rose. This was because
the amount of hydrogen ions caused greater amounts of denatured
enzymes and greater losses of enzymes being able to form an
enzyme-substrate complex. At pH 9 the optimum pH was reached as the
enzyme was catalysing the reaction at the maximum rate and greatest
amount of oxygen was produced. This was because the amount of hydrogen
ions did not affect the ionic bonds of the tertiary structure and the
charges on the amino acids within the active site. Therefore more
substrate molecules could meet and fit the active sites and
enzyme-substrate complexes could be formed and the reaction could take
place. However at pH 11 the amount of gas produced began to fall this
was because the amount of ions in the pH 11 solution caused the
breaking of the ionic bonds that hold the tertiary structure of the
enzyme in place and also effected charges on the amino acids within
the active site, meaning fewer reactions could take place. At pH 13
and 14 I predict the rate of reaction would return to zero, as the ion
content of the pH 13/14 solution would cause the enzymes to denature.

Evaluation

To enable this experiment to be completed as accurate as possible, I
repeated the procedure three times and calculated the average of all
the results, converted them into rate of reaction (cm3/s) and plotted
a graph with a line of best fit. I kept all the variables apart from
the one I was testing (pH) the same. This meant the amount of hydrogen
peroxide remained the same as well as the amount of time the celery
was reacting with the substrate and the size of the celery. I tried to
make the measurements as accurate as possible, however the measuring
cylinders went up in intervals of 1mm3 so my measurements were
accurate to the nearest mm3. There was also a delay between putting
hydrogen peroxide in with the peroxidase solution and placing the bung
on top. However I feel the results are reliable enough to make a solid
conclusion, as there are no anomalous results. To make sure the pH was
not effected I used separate equipment for each pH level instead of
rinsing with water as this would effect the pH level.

Improvements

To improve the results to make them even more accurate and reliable I
would next time cut the weigh the amount of celery to be used or
either use another source such as jarred horseradish as it can be
easily weighed out. I would also use more accurate measuring apparatus
such as a large burette.


Return to 123HelpMe.com