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

The effect of an inhibitor on sucrase activity.

Extracts from this document...

Introduction

Nang The effect of inhibitor on sucrase activity Introduction Sucrase is an enzyme which catalyses the hydrolysis of sucrose into glucose and fructose. The products of the reaction are reducing sugars (glucose and fructose). Like many enzymes, sucrase is a globular protein and its structure is maintained by hydrogen bonds, disulphide bridges and the ionic bond. Sucrase has a specific site called active-site where substrate molecules (sucrose) bind to form enzyme-substrate complex. The shape of the active-site is so specific that only sucrose can fit in. This is called lock and key mechanism and suggests that one enzyme can only catalyse one reaction. However, enzyme slightly changes its shape when substrate binds to its active- site. This process is known as an induced fit. The presence of these molecules can be tested by using Benedict's solution. The reducing sugar means that it can reduce the copper (II) in Benedict's solution into copper (I) which is red precipitate. In this experiment, we are looking at the effect of inhibitor on sucrase activity. Inhibitor is a substance which slows down the rate of enzyme controlled reaction. Hypothesis The rate of formation of glucose and fructose will slow down with the presence of silver nitrate solution compared with the rate of reaction which does not contain silver nitrate. ...read more.

Middle

because (T1) graph is steeper than (T2) graph. This shows that more reducing sugar is being formed from non-inhibited reaction compared with inhibited reaction over the same period of time. The rate of formation of enzyme-substrate complex is higher without the presence of silver nitrate because all the active-sites are available for sucrose molecules to bind and form enzyme-substrate complexes. Enzymes are working at their maximum rate so more and more products are formed as the reaction proceeds. But with the presence of silver nitrate, very few products are formed. This is because silver nitrate binds to sucrase at allosteric sites and causes the change in shape of the enzymes which in turn alter the specific shape of the active-sites. Fewer and fewer active-sites are available for sucrose as the reaction proceeds, resulting in fewer enzyme-substrate complexes. Therefore fewer glucose and fructose are formed. For the reaction in the medium without silver nitrate, we expect the graph to flatten off after a certain period of time. But this reaction cannot give the graph this shape because it needs a longer time for the experiment. At this particular point where the graph flattens off, there can be three possible reasons. * All the substrate molecules are used up during the reaction. The volume of the substrate is constant in the experiment. ...read more.

Conclusion

But we didn't have enough time to repeat the experiment. We also could not get the result until the graph is flatten off which we expect to get. All this could be done if we were allowed a longer time. There was another uncertainty where we had to compare the colour of our result to that of the standard solution. Some of our result did not perfectly match with the standard colour (e.g. the colour lies between 0.22 and 0.17moldm-3) and thus we took the reading between those two readings. This could possibly give us the anomalous points on our graphs. A more accurate reading could be obtained if we used the colorimeter to measure the colour of the solution. This would give us a more reliable result because the colorimeter would be calibrated each time the reading was taken. There was the other way of measuring the concentration of reducing sugar. The precipitate could be filtered out and dried. We could measure the dry mass of the precipitate and work out the concentration of reducing sugar. Other possible coursework This experiment can be adapted to investigate the effect of the following factors on the enzyme activity. 1. The temperature 2. The pH 3. The enzyme concentration 4. The substrate concentration 5. The active-site directed inhibitors ?? ?? ?? ?? 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 Molecules & Cells section.

Found what you're looking for?

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

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 Molecules & Cells essays

  1. Affect of sucrose concentration on the rate of respiration.

    But the disadvantages of this source of information were that it only displayed brief definitions on the topics and does not explain in detail on the main points of the topic. Evaluating all the secondary sources I used I found the best source being the textbooks.

  2. Investigate the effect of sucrase concentration on the rate of hydrolysis of sucrose.

    Lock and key hypothesis description of the specificity of the shape of the active site for a particular substrate. The lock and key hypothesis attempts to explain how enzymes are specific to particular substrates and how they may work. In this hypothesis the enzyme is the lock and the substrate(s)

  1. Investigating the effect of pH on the activity of an enzyme.

    * Measure out 2cm� of this solution using a clean measuring cylinder and pour into a cuvette and place in the colorimeter. > Using the colorimeter * Set the reading to absorption as this is being tested. * Check that the filter is in the correct position all the time.

  2. Investigate the factors affecting the rate of breakdown of sucrose by the enzyme sucrase ...

    This could be a factor to investigate. Volume of substrate (Keeping the volume of sucrase the same and the concentration of both solutions the same). Increasing the volume of sucrose will decrease the rate as there will be more sucrose to be broken down and this will take longer so the rate in slower.

  1. The effect that temperature has on the enzymatic activity of sucrase.

    Furthermore any change in pH affects the ionic and hydrogen bonding in an enzyme and consequently alters it shape. Each enzyme has an optimum pH at which its active site best fits the substrate. Variation in any part of pH will result in the denaturing of the enzyme along with

  2. Investigation into the effect of enzyme concentration of catalysers of sucrose by sucrase.

    amino acids R groups, affecting the way in which they bond which effects the 3D shape of the enzyme and denatures it. 2 If the enzyme concentration is increased the reaction rate will increase because there are more active sites for the substrate to fit into, which means the substrate will be broken down into two or more products quicker.

  1. To investigate how different factors affect the rate of breakdown of sucrose by the ...

    This is time efficient. Increasing the temperature of the substrate means the substrate will gain kinetic energy as the kinetic theory states. Heat is absorbed by particles, which is converted into kinetic energy, causing them to move more rapidly. Obviously if the particles are moving far more rapidly due to

  2. Investigating the effect of sucrose concentration on the conversion into glucose and fructose by ...

    rate at which it can combine with substrate molecules and form enzyme-substrate complex. Between these two concentrations the active sites of all enzymes start to get occupied and at 8% they are all full and cannot release products. At sucrose concentration of 8% enzyme saturation limits reaction rate and further increase will not speed the rate of reaction.

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