Abstract:

This lab was conducted to show and prove the effects of temperature and PH levels on the activity of the enzyme Catalase. First, we found out which item contained the most Catalase by submerging three different items (potato, apple, liver) into Hydrogen Peroxide. Once we found out liver contained the most Catalase we conducted lab 2. In this lab we found out that Catalase works best at 37 degrees and denatures at temperatures above 90 degrees. We did this by heating the Hydrogen Peroxide to different temperatures using water baths. Then we conducted the final lab to test the effects of PH levels by obtaining three different PHs. We had basic, acidic and neutral solutions and after dropping the livers in we found that Catalase works best in neural conditions.

Introduction:

            In this lab we were trying to find out the effects of temperature and Ph on the enzyme Catalase. We started with finding out which item has the most of enzyme Catalase by submerging them into hydrogen peroxide. Then once we had determined the item with the most Catalase in it we tested the effects of different temperatures and PHs.

Enzymes are very important proteins in bodies of plants and animals. Enzymes are proteins that catalyze reactions. They are called catalysts because of this function. Enzymes come from the Greek words In Leaven. Enzymes take a substrate and catalyze the reaction to make the products. The enzyme can help a reaction happen faster but it does not make different products then the one that would have been created without an enzyme.

The first way that was suggested on how enzymes work was by a man named Emil Fischer in 1894. He said that enzymes and substrates bind together like a lock and key. He said that there are very specific enzyme geometric shapes that specific substrates can bond to perfectly. This model was proved wrong. A man named Daniel Koshland changed the lock and key model a bit to make it work. He said that enzymes change shape when the substrate bonds to it. This was called the induced fit model. In an induced fit model a substrate attaches to an active site on an enzyme. Then the enzyme changes shape slightly to let the substrate fit better. When the substrate and the enzyme are linked together it is called the Enzyme/Substrate Complex. Then the enzyme speed up or sometimes slow down the reaction and then the products are released from the enzyme. After this process the enzyme is left unchanged and is ready to catalyze the same reaction again. Enzymes are not changed in the reactions but they can be changed and they can deteriorate if there is too much heat or if it is too cold. This is because enzymes work best at specific temperatures. Changes in Ph can also make an enzyme unable to do its job.

Enzymes need to be regulated so that there is not an over production of unwanted products. The body uses several ways to regulate the enzymes in our body. The first way the body controls enzyme activity is through enzyme inhibition. In this method the body uses inhibitors to control the activity of enzymes. There are 2 types of enzyme inhibition. The first way uses competitive inhibitors which are inhibitors that bind to an active site of an enzyme so that the substrate cannot join up with the enzyme to make the products. The inhibitor is fighting with the substrate to get the enzyme active site so it is called competitive inhibitor. The other way uses noncompetitive inhibitors which do not need to compete for an active site. These inhibitors can bind with an enzyme somewhere other than the active site. Once these inhibitors are joined up with the enzyme it makes the enzyme change shape so that it cannot combine with the substrate or it may change the enzyme function so that it cannot do what it was meant to do. The second way the body regulates enzymes is through allosteric regulation. In this way an allosteric inhibitor which is like a noncompetitive inhibitor binds to an allosteric site. Allosteric sits are site on an enzyme other than the active site where substances may inhibit or simulate enzyme activity. When an activator is bound to the allosteric site this stabilizes the enzyme to keep its active site open for its substrate. When an allosteric inhibitor is joined up with the allosteric site then the enzyme becomes stable and is also unable to catalyze its reaction. The last way the body can regulate enzyme activity is through feedback inhibition. Feedback inhibition works by using a product that would be produced later on in a series of reactions using catalysts to allosterically inhibit an enzyme earlier in the series of reaction. This involves the reactions to make products which also act as inhibitors to the enzymes. If there is a lot of products then more enzymes will be inhibited which decreases the production of the product. After some time the products are used up and less enzymes are bring inhibited so the enzymes make more products and the cycle goes on.

            There are several factors the effect enzyme activity. Every enzyme has a specific temperature that it works best at when this temperature goes above or below the one needed for the enzyme then the enzyme starts to slow down its activity. If the temperature is too high the enzyme will denature and be unable to function. Also if the temperature is too low the enzyme will lose its function. Another thing that affects enzyme activity is the ph level of its environment. Just like every enzyme has a specific temperature it works at every enzyme also has a specific Ph it works best in. Different enzymes have different conditions they work best in. The activity of the enzyme can also be effected by the amount of reactants present and also if there are inhibitors or activators present.

            I think that in lab # 2 the Catalase will have a temperature close to our body temperature that it will work best at and then other temperatures it might work less with. I think as the temperature gets higher the enzyme Catalase will work less effectively and after a certain temperature it might not work at all. For lab #3 I think the Ph the enzyme will work best in will be neutral because a big portion of the liver would be water and it would produce enzymes that work best in neutral conditions because water is neutral.

 

 

 

 

 

 

Purpose:

The purpose of this lab is to determine the effects of temperature and PH levels on the biological enzyme Catalase.

Materials:

Lab #1:

• Potato
• Cow Liver
• Apple
• Scalpel
• Graduated Cylinder
• Hydrogen Peroxide
• Test Tubes

Lab #2:

• Liver
• Scalpel
• Test Tubes
• Hydrogen Peroxide
• Tap Water
• Ice Cubes
• Dropper
• Hot Plates
• Thermometers
• Test Tube Tongs
• Test Tube Rack
• Graduated Cylinder

Lab #3:

• Test Tubes
• Hydrogen Peroxide
• Tap Water
• Sodium Hydroxide
• PH Paper
• Graduated Cylinder
• Dropper
• Scalpel
• Hydrochloric Acid
• Stirring Rod

 

 

 

Procedure:

Lab #1:

1)      The potato, apple and liver were cut into equal sized pieces using a scalpel.

2)      2mL of Hydrogen Peroxide was measured and added to the test tube using a dropper.

3)      Step 2 was repeated for the remaining 2 test tubes.

4)      The potato, apple and liver pieces were dropped into the separate test tubes.

5)       Observations were made and ratings were recorded.

 

Lab #2:

1)      6 Pieces of liver were cut each of equal size using a scalpel.

2)      6 Graduated Cylinders were filled with tap water.

3)      Water in the graduated cylinders was brought to the correct temperature using  

       hot plates and ice cubes.

4)      Test Tubes were filled with 2mL of Hydrogen Peroxide using a dropper.

5)      Each test tube was placed in a graduated cylinder.

6)      The test tubes were left in the graduated cylinders for 3 to 4 minutes.

7)      The liver was added to the graduated cylinders.

8)      Observations were made and ratings were recorded.

Lab #3:

1)      3 Equal sized liver pieces were cut out using a scalpel.

2)      2mL of Hydrogen Peroxide was measured and added to the test tubes.

3)      Hydrochloric Acid was added to the first test tube until PH 3 was reached.

4)      Sodium Hydroxide was added to the second test tube until PH 10 was reached.

5)      Tap water was added to the third test tube until PH 7 was reached.

6)      Liver Pieces were added to each of the solutions.

7)      Observations were recorded and ratings were recorded.

 

 

 

 

 

 

 

 

 

 

 

 

 

Observations:

Lab #1:

Ratings Of The Reactions For Different Items
Items	Rating
Potato	3
Liver	5
Apple	1

Lab #2:

Ratings Of The Reactions For Different Temperatures
Temperature (oC)	Rating
0	3
20	4
37	5
60	5
80	2
100	1

Lab #3:

Ratings Of The Reactions For Different PH Levels
PH Type	Rating
Basic (10)	4
Neutral (7)	5
Acidic (3)	1

 

 

 

 

 

 

 

Results:

Lab#1:

Discussion:

This lab illustrated the effects of temperature and PH on the enzyme Catalase. As we know the enzyme should work the best at certain temperature and PH. When we conducted this lab this held true and the Catalase worked best at certain temperatures and PHs and worse at others. Some things that could have affected the results of this lab are that temperatures and PHs may not be as accurate as we stated. The temperature is hard to control and for PHs it’s hard to get them exactly where what we need them at. Using a more accurate instrument to measure PH would help and some how getting the temperature at the exact degree would help.

            Catalase is an enzyme in the body that catalyses the reaction of Hydrogen Peroxide to form water and oxygen. Catalase is a polymer that has 4 polypeptide chains. Every chain has more than 500 amino acids. The chain also has 4 porphyrin heme groups. These groups control the Catalyses’ activity. Catalase is stored in the cell organelle called the Peroxisome. Peroxisomes oxidate fatty acids which produces Hydrogen Peroxide. White cells also produce Hydrogen Peroxide to kill bacteria. Catalase is stored in the cells so that the Hydrogen Peroxide does not harm the cell itself. Catalase is found in all living tissues of the body. As we see in lab one different tissue have different amounts of Catalase in them. Tissues of apple have less Catalase then the tissues of the liver. As with all enzymes Catalase is also affected by temperature and PH levels. As we see from Lab #2 Catalase works best at temperatures of 37 degrees and 60 degrees. When the temperature gets higher Catalase works less effectively and as it reaches 100 degrees it is denatured and hardly works at all. With PH the Catalase works best in neutral solution which gave the best reaction and then it works slightly less in a basic solution and it almost does not work in an acidic environment. According to literature Catalase is suppose to work the best at temperature of the body which is 37 degrees. Catalase is an enzyme so it is reusable. Catalase is one of the fastest enzymes we know of. Catalase can catalyze 100 million molecules of Hydrogen Peroxide per second and produce water and oxygen. Pepsin is an enzyme found in the stomach of the body and is responsible for breaking down proteins. Pepsin catalyzes the hydrolysis of proteins to make polypeptides.  Bacteria have enzymes inside their cell walls but it is not inside an organelle. Some bacteria are inside organisms that have Hydrogen Peroxide in them and the bacteria might need to break it down.

 

Conclusion:

We found out that Catalase is most active at the temperature of 37 degrees and as the temperature gets lower or higher then that the Catalase works less effectively. Catalase also works the best in Neutral conditions according to Lab #3.

 

 

 

 

 

 

 

References:

Bennett T. P, and Frieden E. “Factors Affecting Enzyme Activity (Introduction to Enzymes).” Enzymes, Biochemicals: Worthington Biochemical Corporation. Worthington-Biochem, 2009. Web. 13 Oct. 2009. .

“Catalase, Lactase, Catechol Oxidase Enzymes.” Collaborative science projects. Science-projects. Web. 15 Oct. 2009. .

Haley, Patrick. “Bacteria.” CareFree Enzymes. Care Free Enzymes, 2008. Web. 13 Oct. 2009. .

“Pepsin Facts, information, pictures.” Encyclopedia – Online Dictionary | Encyclopedia.com: Get facts, articles, pictures, video. The Columbia Encyclopedia, 2008. Web. 13 Oct. 2009. .

 

 

 

 

 

 

 

 

 

 

Catalase Enzyme Lab

Friday, October 16, 2009

Jenish Patel

576364

Mr.Steadman

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DNA Structure

 

DNA is made up of deoxyribose sugar phosphate group (negatively charged) and a nitrogenous base.

 

Purnes Adenine, Guanine

Pyrimidines Thymine , Cytosine

DNA has a double helix structure and the helix runs in an antiparalleel manner. This means the 5 end of the DNA is aligned with th 2 end of it and it is backwoards but parallel.

 

DNA also has complementary base pairing so the pairing do nitrogenous base with them pairs.

 

The history of DNA

Fired Mieshor – swiss biochemist investigated chemical compositions of DNA using pus cells.

JOachin Hammelyy discovered the location of DNA by cutting off caps and foots

 

Alfred Hershey and Martha Chase

Did experiments to show DNA was hereditary material

 

Ervin Chargaff discovred that the amount of adenine and thymine is equal and the amount of cytosine and guanine is also equal Therefore the Purines and prrimideines are equal in amounts.

 

Rosalind Franklion

Got a image from crystallograpgy to fiund the heilz sturcutnre of DNA