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

Measuring the effect of pH on phosphatase activity.

Extracts from this document...


Measuring the effect of pH on phosphatase activity Catalysts play an extremely important role in our lives, they are used in the manufacturing of important chemicals we use, and are present in our body. A catalyst affects the rate of a reaction, usually speeding it up. Biological catalysts, such as those present in our body, are called enzymes. These enzymes help speed up reactions in our body by up to a billion times! To understand how enzymes work, we must first find out what exactly they do and what they are. Enzymes are made from proteins; and proteins are made from complex chains of amino acids folded over into either a secondary or a tertiary helix, and held together by sulphur and hydrogen bonds. An enzyme has an active site, which is where the substrate joins, and the reaction happens. Enzymes are specific to the reaction there are involved in. The active site will only react with substrates that fit exactly in the active site. This is called the lock and key theory, this theory was later improved on, by the suggestion that enzymes had a certain amount of 'flexibility' in that inhibitors would fit in the active site, even though it isn't meant to. This is called the induced fit theory. ...read more.


stop reaction by adding 2.5 ml of 10% sodium carbonate, 9. measure colouration using calibrated cards, and colorimeter Equipment Test tubes Pestle and mortar Substrate PPP Mung beans Buffer- of different concentrations, ranging from 2.2-9.2 Sodium carbonate Pipettes By adding sodium carbonate, this it will cause the reaction to stop, and any phenolphthalein to turn pink. It is the colouration of the pink that I will be observing and distinguishing the results. I have chosen to use 8 different buffers of different ph levels; 2.2, 3, 4.2, 5, 6, 7, 8 and 9.2. I tested the pH level of each of the buffers and these are the results I got, that is why same have a reading of .2, however this will make no difference to the experiment. The level of pH is my only variable. As with all experiments, you should only change one thing at a time, keeping all other aspects that may affect the results the same. Because the enzyme mixture will be used for all the experiments, the concentration will be the same. If the concentration were to be different, the experiment with greater enzyme concentration would have a result that would show a greater colour change. Due to there being more enzymes, a greater rate of reaction can be reached. ...read more.


You can tell from my results that the enzyme is very inefficient in alkali environments; there is a great decline in production of phenolphthalein when you start getting below pH 7. Whereas the production of phenolphthalein in an acidic environment as a much less rapid decline. The ionic boning between the amino acids in the proteins which make up the enzyme must break quicker in an alkali environment. The breaking of the bonds allows the enzymes' active site to become misshaped; this means that the rate of reaction is reduced because it is taking longer for the enzyme to join with the substrate to form a substrate-complex and break them up into the products; phosphate and phenolphthalein. There are very few anomalies, the main one which is most faulty is the pH 6 experiment, were there is a difference of 12, however this is quite small, and doesn't really affect the overall result of the experiment. As I said before, this might be due to many reasons; a misread on the colorimeter, experiment having longer time, exposed to different temperature/amount of light. To expand on the investigation I would re-do the experiment, but my range of buffers would be less. I would probably use buffers ranging from pH 5 to pH 7 to get a more exact reading on what the most effective pH level is. ...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. Investigating the effect of pH on the activity of an enzyme.

    ==> Bunsen burner: to denature the enzyme for the control solution. ==> Colorimeter and cuvettes: these are used to measure the absorbency to see how the pH has affected the activity of the enzyme. ==> Ruler: to measure the exposed photographic strip accurately ==> Measuring cylinder: to measure the exact amount of solutions accurately.

  2. Investigating the Effect of pH on Enzymes

    Changes in pH can affect the rate of reaction as the hydrogen ions can affect the hydrogen bonding in the tertiary structure. Small changes will not denature the enzyme but extreme changes will affect the shape. The introduction of H+ (acidity)

  1. An Investigation on the Effect of Inhibitor Concentration on Reactions involving Acid Phosphatase.

    Enzyme Theory Enzyme: Biological catalyst Catalysts assist reactions but do not start a reaction that would not occur spontaneously without a catalyst. Catalysts work by lowering the activation energy of a reaction [6]. In the reaction being investigated the compound phenolphthalein diphosphate is the substrate and phenolphthalein and phosphates are the products.


    I will keep the temperature of this experiment at 40oC, because the enzyme amylase can be used between 20 and 60oC and its optimum is 50oC, therefore the enzyme will work perfectly well as the temperature I want to use is not far above or far below its optimum.

  1. An investigation into the factors that affect the amount of phosphate produced in the ...

    * Once 30 minutes has passed I will take the tubes out of the water bath and add the sodium carbonate solution to each tube to stop the reactions. The solutions will turn magenta and using the magenta filters I will record the strength of the solutions according to the filters.

  2. The effect of Electromagnetic Fields on Enzyme Activity

    Magnetite is found in mammalian cells, and in humans it was recently discovered to be situated in brain tissue, in the ethmoid bone above the eyes, in the sinuses and in the blood-brain barrier. In other animals whiskers, and insect antennas, also seem to be a tool to feel the

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