• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigation of Enzyme Activity

Extracts from this document...


An Investigation of Enzyme Activity with different Substrate Concentrations. Aim To investigate how different concentrations of substrate affects the rate of enzyme activity. Objective My objective is to determine how different concentrations of substrate, affects the rate of enzyme activity. I will do this by using different concentrations of Hydrogen Peroxide, and mixing it with the enzyme catalyse. Then I will measure how much gas is produced. Theory What is an Enzyme? Enzymes are proteins which are biological catalysts. A catalyst in chemical terms substantially reduces the energy barrier which exists between atoms and which prevents the atoms from getting close enough to react and form a bond with one another. An enzyme lowers the energy of activation of a reaction but the catalyst is not changed in any way in the process .Therefore, when the atoms of molecules are acted upon by enzymes, an identical reaction occurs as would have occurred without the enzyme but, the energy hill required to overcome the getting-close barrier, is much, much smaller than would have been true without the enzyme's help. The structure of the enzyme is such that atoms of molecules can get close enough to interact, but the energy required to allow this closeness is relatively small. ...read more.


The substrate can no longer bind, and the reaction is no longer catalysed. At very high temperatures this is irreversible. Only the weak hydrogen bonds are broken at these mild temperatures; to break strong covalent bonds you need to boil in concentrated acid for many hours. 2. pH Enzymes have an optimum pH at which they work fastest. The pH affects the charge of the amino acids at the active site, so the properties of the active site change and the substrate can no longer bind. Table II pH for Optimum Activity Enzyme pH Optimum Lipase (pancreas) 8.0 Lipase (stomach) 4.0 - 5.0 Lipase (castor oil) 4.7 Pepsin 1.5 - 1.6 Trypsin 7.8 - 8.7 Urease 7.0 Invertase 4.5 Maltase 6.1 - 6.8 Amylase (pancreas) 6.7 - 7.0 Amylase (malt) 4.6 - 5.2 Catalase 7.0 3. Enzyme concentration As the enzyme concentration increases the rate of the reaction increases linearly, because there are more enzyme molecules available to catalyse the reaction. At very high enzyme concentration the substrate concentration may become rate-limiting, so the rate stops increasing. Normally enzymes are present in cells in rather low concentrations. 4. Substrate concentration The rate of an enzyme-catalysed reaction shows a curved dependence on substrate concentration. ...read more.


I say this because of my theory. As the substrate concentration increases, the rate increases because more substrate molecules can collide with enzyme molecules, so more reactions will take place. However I predict that the enzyme will be a limiting factor after a certain concentration, and therefore the fate of reaction will not go any faster. This is because there are no more available active sites to increase the rate of reaction. . At higher concentrations the enzyme molecules become saturated with substrate, so there are few free enzyme molecules, so adding more substrate doesn't make much difference I believe my graph will look like this because of my prediction. Equipment 8 Test Tubes with Bungs with holes in them 20 mls of 0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2 Mol/dm3 Test Tube Rack Distilled Water 100ml Gas Syringe Stop Clock 100 mls of Catalyse Pipette Method 1. Using the Pipette, put 5mls of Catalyse into each of the 8 test tubes. 2. Then put 5mls of Hydrogen Peroxide at 0.4 Mol/dm3 into the first test tube. 3. Then quickly attach the 100ml Gas Syringe to the test tube. 4. Collect gas produced for 5 minutes. Use the stop clock to time your experiment. 5. Record your results, and then repeat the procedure. 6. Then repeat the whole procedure, this time for a different concentration of Hydrogen Peroxide. ?? ?? ?? ?? 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Inorganic Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

5 star(s)

This is a very in depth and detailed account of the biochemistry of enzymes. It is written in a clear and logical manner and contains advanced theorys.

Marked by teacher Brady Smith 17/07/2012

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Inorganic Chemistry essays

  1. Peer reviewed

    Determining the concentration of acid in a given solution

    5 star(s)

    then fill the volumetric flask up with distilled water, so that there is a know concentration of the solution. The error on a 250cm3 volumetric flask is 0.2cm3 if read correctly. This means that the percentage error is 0.08%. This is a very low percentage error for the volumetric flask

  2. Bleaching experiment. Estimation of available chlorine in commercial bleaching solution.

    The volumetric flask was stoppered and was inverted it for several times. (to ensure the solution mix well) 8. Step (1) was repeated for the pipette and then was rinsed with the diluted bleach. 9. 25cm3 of the diluted bleach was pipettedinto a conical flask. (Pipette filler was used.)

  1. determination of the percentage of oxalate in iron (II) oxalate by redox titration

    24H+ +5FeC2O4 � 3Mn2+ + 10CO2 + 5Fe3+ + 12H2O As 17.3 cm3 of MnO4- is used, no. of mole of MnO4- = 0.02007 x (17.3 � 1000) = 0.000347211 mol. Mole ratio of MnO4- to FeC2O4 = 3:5 No. of mole of FeC2O4 (10 cm3) = 0.000578685 mol. No.

  2. Lab report Determination of Enthalpy Change of Neutralization

    51.2 36.2 100 35.8 35.2 33.5 35.8 51.2 36.2 105 35.8 35.2 33.5 35.8 51.0 36.0 110 35.8 35.2 33.5 35.8 51.0 36.0 115 35.5 35.0 33.5 35.8 51.0 36.0 120 35.5 35.0 33.2 35.5 50.8 36.0 Reaction 1 Reaction 2 Reaction 3 Reaction 4 Reaction 5 Reaction 6 Volume

  1. an experiement to test for anions and cations

    Gloves should be worn, with both gloves and hands being thoroughly washed when finished with the experiment. Fume cupboard Should be switched on to provide ventilation for any toxic/pungent fumes. Method Testing for cations (Substance I) 1. A small spatula of substance I was added to a test tube, along with distilled water filling half of the test tube.

  2. Aim: To determine the activation energy of the reaction between bromide ion and bromate(V) ...

    to be measured. This will cause a great error in time reading 5. Why is it not necessary to know how far the reaction has proceeded at the point where the methyl red is decolorised? Because the volume of bromine produed in every experiments are the same,so it cannot find

  1. Essay on the Oxides of Period 3 Elements

    However, aluminium oxide does react with both acid and bases since it is amphoteric in nature. For example, aluminium oxide reacts with hydrochloric acid to form aluminium chloride and water as shown in the following equation: It reacts with bases like sodium hydroxide to form sodium tetrahydroxoaluminate.

  2. The aim of this investigation is to analyse what cations and anions are present ...

    level Wash eyes thoroughly with clean water Barium chloride Toxic Skin contact Inhalation Always keep a lab coat on High risk level If contact with skin wash with clean water immediately Lithium Chloride irritant Harmful if swallowed Wear gloves and proactive clothing Low risk If inhaled get medical help as

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work