An investigation of the enzyme catalysed hydrolysis of urea - To find out how long the urease takes to produce an alkaline solution at a known concentration of urea and urease, and at room temperature.

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AMAN SINGH SUMAL

AN INVESTIGATION OF THE ENZYME –

CATALYSED HYDROLYSIS OF UREA

AIM:

  1. To find out how long the urease takes to produce an alkaline solution at a known concentration of urea and urease, and at room temperature.
  2. To use similar substrates urea, ethanamide and methylurea, to test the specificity of the enzyme.
  3. To enable you to plan a more extensive investigation of the properties of urease.

BACKGROUND INFORMATION:

Urease appears as a white powder, which can be found in both plant and animal cells. This powder can be found in certain plant seeds, for example, watermelon or jack beans, it can also be found in the cellular structure in our bodies.

Urease is made to use generated urea as a nitrogen source, as this is the enzyme that controls urea decomposition.  However it also has many other uses.

Another example of its uses can be found in plants.  As urease helps in the systemic nitrogen transport pathways, and can also act as a toxic defence protein.  Urease in our bodies is only used through excretion purposes, as urea is broken down into two products, ammonia and carbon dioxide.  These can easily be excreted through the cell by exocytosis, which then can be removed from the body though mouth, nose, urine, faeces etc.

Urease can also be used in industry for many treatments and to test for medical conditions.

The reactions happening in this experiment would have happened inside animal and plant cells.  In animals, urea is broken down in the gastricmucosa found in the stomach, by the enzyme urease.  Urea is broken down into carbon dioxide and ammonia.  In plants it is used to help increase the overall efficiency of the plants nitrogen use.

This background knowledge explains how important biologically urease is needed, in breaking down urea into simpler substances, which can be excreted easier.  It shows how without it, it could lead to problems concerning our future existence.

Enzymes are large proteins that speed up chemical reactions. In their structure, polypeptide chains twist bringing together amino acids to form the active site.  The active site is the location enzyme where the substrate binds and the reaction takes place.

If the enzyme and the substrates shape is not exactly the same, they will not bind together, causing the substrate not to be broken down.  This maybe due to too much heat, as enzymes optimum temperature is at 37ºC, and the enzyme denature. The enzyme itself is unaffected by the reaction. When the products have been released, the enzyme is ready to bind with another substrate.  The diagram on the last page shows how the substrates binds with the enzyme and then gets broken down.

Enzyme Uses – enzymes can be used in genetic engineering.  This diagram below show the stages in genetic engineering, and how enzymes play a major role in allowing this process to happen.

  1. In genetic engineering, scientists use restriction enzymes to isolate a segment of DNA that contains a gene of interest, for example, the gene regulating insulin production for diabetes.
  2. A plasmid extracted from its bacteria and treated with the same restriction enzyme can hybridize with this fragment’s “sticky” ends of complementary DNA.
  3. The hybrid plasmid is reincorporated into the bacterial cell, where it replicates as part of the cell’s DNA.
  4. A large number of daughter cells can be cultured and their gene products extracted for human use.

Enzymes can also be used in alcoholic fermentation and other important industrial processes.  In this area the action of enzymes that are synthesized (made) by the yeasts and bacteria used in the production process. A number of enzymes are used for medical purposes, e.g. producing insulin for diabetics. Some have been useful in treating areas of local inflammation; trypsin is employed in removing foreign matter and dead tissue from wounds and burns.

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The background information about enzymes has been taken and edited from Microsoft Encarta 95.

This background knowledge emphasises the significance of enzymes to humans and how they help us in many ways.

PREDICTION:

I predict that when testing the specificity of the enzyme, the more similar the substrate is used the easier it would be to be broken down.  This is because the rate of reaction would be quicker, due to the urease being able to break down the substrate quicker, therefore creating a bigger surface area for the urease enzyme to work on.  The stronger ...

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