The effects of temperature, PH and enzyme concentration on enzyme activity.

Table of Content


  1. To analyze the effects of temperature on enzyme activity.
  2. To look into the consequence of pH on enzyme activity.
  3. To analyze the consequence of enzyme concentration on enzyme activity.
  4. To look into the catalase activity in different tissues.

Materials/ setup:

  1. Test tubesLiver puree 3 % ( v/v ) Hydrogen2Oxygen2
  2. PipetteChicken puree 01. M Na citrate buffer solution
  3. Deionized waterApple puree
  4. ThermometerPotato puree
  5. Carrot puree



Enzyme Activity ( 1-5 ) Description
Positive Control 0 No bubbles produced
Negative Control 4 Bubbles produced overflow

Did the reaction give off heat?Yes

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Consequence Of Temperature On Enzyme Activity

Temperature ( IS C ) Enzyme Activity ( 1-5 )
Tube 1 ( ice bath ) 2 2
Tube 2 ( room temperature ) 26 4
Tube 3 ( 37 IS C ) 37 5
Tube 4 ( 100 IS C ) 100 0

Is there a temperature at which the catalase activity was the most effectual? Was it the temperature you were anticipating? IF it was non, how can you explicate the consequences? The temperature at which the catalase activity was the most effectual is 37 IS C. Yes, it was the temperature that I was anticipating.

Why put the tubing of H2Oxygen2( and non merely the liver tubing ) into the H2O baths? To obtain the several temperature which is the same with the temperature of the liver puree so that the consequences obtained is more accurate.

Consequence Of pH On Enzyme Activity

Enzyme Activity ( 1-5 )
pH 3 2
pH 7 4
pH 11 1

At what pH does catalase exhibit the greatest activity? pH 7 exhibit the greatest activity. Plot a graph ( enzyme activity vs pH ) that correspond with the consequences of your trial.

Consequence Of Enzyme Concentration On Enzyme Activity

Enzyme Enzyme Activity ( 1-5 ) Description
100 % 5 Bubbles overflow
10 % 2 More bubbles are produced
1 % 1 Less bubbles are produced

Were the consequences of this experiment as you expected? If they were non, can you explicate why they were non? Yes, the consequence of the experiment was as I expected.

How effectual is catalase? In this experiment apparatus, do you believe you would observe a difference in reaction rates between a 100 % and a 50 % liver solution? The catalase is really effectual. 50 % enzyme green goods less bubbles and respond slower with H peroxide compared to 100 % enzyme concentration.

Catalase Activity In Different Tissues

Tissue Enzyme Activity ( 1-5 ) Description
Liver 5 Bubbles overflow
Chicken 2 Less bubbles produced
Apple 0 No bubbles produced
Potato 3 More bubbles produced
Carrot 1 Less bubbles produced

What make your consequences tell you about the maps of the different types of tissues? Different types of tissues have different concentration of accelerator, therefore bring forthing different consequences.

Why is it of import that the puree of each substance is obtained by intermixing the same sum of substance in a similar volume of H2O? It is of import in order to accomplish the same concentration of substance.


Enzymes are proteins that map as biological accelerators. They can assist to change or rush up chemical reactions. At the terminal of each reactions, they will stay chemically unchanged. Enzymes speed up chemical reactions by take downing the activation energy which is required to get down a reaction. They provides an alternate tract with lower activation energy for reaction to take topographic point. Since enzymes are really efficient molecules and remain unchanged during chemical reactions, the same enzymes molecules can be used once more and once more.

Therefore, merely a little sum of enzymes is required to catalyze a big figure of chemical reactions. Enzymes are specific, undergoing ‘Lock-and-key’ hypothesis. Harmonizing to this hypothesis, enzyme reaction depends on the presence of active sites. The enzyme is the lock and the substrate is the key. The manner of action of an enzyme is as below. An enzyme has a specific 3-dimensional ( 3-D ) form, with a depression, active site. Merely the substrate with a 3-D form complementary to that of the active site can merely suit into the enzyme. This is the formation of enzyme-substrate composite.

The substrate will adhere to the active site of the enzyme. Chemical reaction occurs while substrate is attached to the enzyme. During this procedure, the substrate is so converted to merchandises. The general equation is: Enzyme + Substrate Enzyme-substrate Enzyme +Product. At the terminal of the reaction, the merchandises will go forth the active sites, go forthing the enzyme chemically unchanged.

However, enzymes are affected by a few factors such as temperature, pH value and besides concentration of enzyme- substrate. Enzymes are most active at optimal temperature about 36 – 37.5 IS C. They are normally inactive, but non destroyed at low temperature as the kinetic energy will be low. This causes the opportunities for the substrate molecules to clash with the enzyme is really low. With an addition in temperature ( non over the optimal temperature ) , the rate of enzyme reaction and formation of enzyme-substrate composite will increase.

For every rise in 10 IS C in temperature, the rate of enzyme reaction is doubled, until the optimal temperature is reached. If the addition of temperature is over the optimal temperature, the bonds that keep the enzyme in form will be broken, doing the active site of the enzyme to lose form. The substrate can no longer suit into the active site and the enzyme is said to be denatured. It no longer can move as a accelerator. Most enzymes are wholly denatured at a temperature of 60 IS C.

Furthermore, enzymes are affected by the pH of solution. Some enzymes work best in different pH, some work best in acidic solution while some in alkalic solution. For illustration, the optimal pH for amylase in spit is pH 7, pepsin in tummy is pH 2 and trypsin in little bowel is pH 8. Extreme alterations in the pH of the solutions denatures the enzymes.

Last, enzymes are affected by enzyme and substrate concentration. As the concentration of enzyme and substrate addition, the rate of reaction besides increases. For a given concentration, the rate of reaction additions with an increasing concentration of substrate up to a certain point. There will be no important alteration in the rate of reaction as the substrate concentration increases more than that peculiar certain point. This happens as the active sites of the enzyme molecule at that clip will be saturated with substrate. Active sites are able to suit more substrate after the enzyme-substrate composite has dissociated. However, the rate of reaction will be relative to the enzyme concentration if the substrate concentration is high plenty and the temperature and pH value is kept changeless.

  1. The optimal temperature for enzyme activity is 37 IS C.
  2. The pH 7 allows catalase to exhibit the greatest activity.
  3. The enzyme activity is the most effectual when enzyme concentration is 100 % .
  4. Liver puree has the highest enzyme activity.


  1. List the conditions you tested to find which catalase exhibited the greatest activity. How do these conditions compare to those of a cell in the organic structure? The conditions tested are temperature, pH value and enzyme concentration. Since our organic structure temperature differs from clip to clip, the conditions required besides varies every clip. Each organic structure portion requires different pH value, so pH value varies in different parts of the organic structure. The enzyme concentration is besides dependent on our province of organic structure and the sum of enzyme secreted by our variety meats.
  2. Hydrogen2Oxygen2is normally used as a germicide for scrapings and cuts. What precisely are you seeking to make when you apply H2Oxygen2to your scraped knee? What on your articulatio genus causes the H2Oxygen2to bubble up when you apply it? Hydrogen2Oxygen2Acts of the Apostless as a lesion sanitizer. Scrapes and cuts open up tegument lesion to blood and amendss cells, which contain an enzyme called catalase. H2Oxygen2bubbles up when applied as the catalase in blood comes in contact with H2Oxygen2, turning H2Oxygen2into H2O ( H2O ) and O2( O ) .
  3. The Browning that occurs when fresh murphies and apples are cut is a consequence of this reaction: Why do mashed murphies remain white? Raw murphies contain enzymepolyphenol oxidase that will oxidise and turn murphies brown in contact with air. However, mashed murphies are cooked murphies, doing the enzymes to denature and will non oxidise the mashed murphies. Hence, mashed murphies remain white alternatively of brown.
  4. Some people put fresh lemon juice on fruit salad to maintain it from browning – what might the chemical account be for this pattern? Lemon juice contains citric acid of pH 3. The high concentration of acidic citric acid stops chemical reaction to happen. This will maintain fruit salad fresh from browning.
  5. ( a ) The U.S. Food & A ; Drug disposal recommends that cooked beef be refrigerated for no more than 3-5 yearss before it is eaten ; for cooked fish they recommend merely 1-2 yearss. Why do you believe fish might non maintain as long in the icebox?
  6. Fever is a common symptom of a viral or bacterial infection. What are two different maps of a rise in organic structure temperature in this instance? What would the danger be if the temperature got excessively high ( above approximately 42 IS C, in worlds ) ? Fever is of import in the constituent of immune respond. The addition in body temperature helps to suppress the growing of bacteriums but at the same clip increasing the rate of chemical reactions that help body’s cell to mend themselves. Besides that, the rise in organic structure temperature AIDSs in increasing the bosom crushing rate that will rush up the circulation of blood in the organic structure so that white blood cells are able to get more rapidly to the infected organic structure parts. However, a high temperature will be a danger to human organic structure, particularly immature kids. High febrility will more likely to trip ictuss in kids or the febrility might be accompanied with serious infection that should be brought to immediate attendings of physicians for exigency intervention.


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