Investigating the inhibition of copper sulphate between an enzyme and substrate Essays

Investigating the inhibition of copper sulphate between an enzyme and substrate Essays Investigating the inhibition of copper sulphate between an enzyme and substrate Essay Investigating the inhibition of copper sulphate between an enzyme and substrate Essay In this investigation I will be carrying out an experiment to see how the addition of copper sulphate to the reaction between hydrogen peroxide and carrots is effected. This is a simple model showing how inhibition (copper sulphate is inhibitor) takes place between an enzyme (carrot) and substrate (hydrogen Peroxide). It will most likely show the effect of a competitive inhibitor as the more inhibitor you add to the reaction between the enzyme and substrate, the slower the reaction between the substrate and enzyme will slow down. I will know how well the reaction (enzyme and substrate binding) is going by collecting the amount of gas (oxygen) given off in the reaction. Obviously if there is a lot of gas given off then the reaction will be faster than if the reaction is slow. I will be going through what my investigation is about and developing a prediction about my investigation. I will then go through some information about information and inhibition and tell you what I know about them. After that I will introduce you to my pre-tests and how I came about to choose the method that I used in the end. I will then talk about what I will need to take account for when doing my investigation, such things as what Ill need to carry out the investigation, what precautions I will take and what things will be done throughout the tests that I do. I will include tables and graphs to show my results and finally conclude my results and finish my investigation by evaluating how well my investigation went. Prediction I predict that when copper sulphate (inhibitor) is added to the hydrogen peroxide (substrate) and carrot (enzyme) it will make the reaction between the enzyme and substrate slower as the copper sulphate will inhibit the enzymes. I also predict that the copper sulphate is a competitive inhibitor otherwise if it were a non-competitive inhibitor the reaction between the substrate and enzyme would not affected in a way that there would hardly be a reaction. I predict that the more substrate there is then the more reaction (substrate binding onto enzymes) will take place. Background Knowledge From class work and essays I already know this information about enzymes:- Most Enzymes are proteins and can be described as catalysts. The majority if not every metabolic reaction which takes place within a living organism is catalysed by enzymes. Enzymes are globular proteins. Like all globular proteins, enzyme molecules are coiled into a specific three-dimensional shape with side chain hydrophilic R groups on the outside of the molecule. This ensures that the enzyme is soluble. Enzymes have a special feature and this is that they posses an active site. This is a region on the enzyme to which another molecule or molecules can bind onto it. This is the substrate of the enzyme. The shape of the specific shape allows the substrate to fit in just right. Also it is held by temporary bonds. This is called the enzyme-substrate complex as a simplified diagram on the next page shows. Each type of enzyme acts on a specific type of enzyme that the enzyme is fit to do as the shape of its active site has a specific shape that only allows that one type of substrate to fit in. The enzyme may catalyse a reaction causing the substrate molecule to split (2 or more) as shown in the diagram. Alternatively catalysing may cause a joining of two molecules. After this process the molecules leave the unchanged enzyme leaving it for another substrate molecule to go and bond onto it. There may be one specific substrate that fits into a specific enzymes active site but there is a possibility for another molecule very similar to the enzymes substrate which can also fit into the active site. This inhibits the enzymes function. This causes competition between the substrate and the enzyme to inhibit the enzyme. If there arent many Inhibitors present then the binding of substrate to enzymes wont be affected but if the substrate was low in concentration compared to the inhibitor then the less likely the substrates will occupy the enzymes active site. This is known as competitive inhibition. In other cases an inhibitor can occupy an enzymes site permanently and therefore will not allow a substrate to bind onto the active site. This is known as non-competitive inhibition and is irreversible. Another form of non-competitive inhibition is when a bacteria can bind somewhere else on the enzyme rather than on the active site. This may result in the enzyme becoming mishapened and disrupts the enzymes arrangement of hydrogen bonds and hydrophobic interactions. Using this simple table you can decipher whether or not if an inhibitor is a competitive or non-competitive inhibitor. Source for background knowledge: Biology 1 (Cambridge, endorsed by OCR). Preliminary Work Before I began my actual investigation I had to decipher what apparatus I would need and what the best method of getting a fair test would be. There was an option of using a glass syringe to collect the gas given off or to use a measuring cylinder in a bucket of water. I also had to comprehend how much carrot gratings and hydrogen peroxide I would require. The method I chose to test out first was the one with the measuring cylinder as I had the notion that not much gas would be given off. I set up my apparatus as shown in the diagram: After deciphering how much hydrogen peroxide (ml) and carrot grating (weighed in grams) I would need I carried out the experiment. At first the reaction went hastily so I tried different amounts of carrot grating and hydrogen peroxide and the results turned out to be similar to the first test. There was clearly too much hydrogen peroxide and carrot gratings as substrate molecules were binding onto the enzyme at a quick rate because a lot of oxygen was being given off and also some of the hydrogen peroxide made its way into the bung. After some deliberation I decided to opt for the glass syringe method as it seemed to be more appropriate. So again like before I set up the equipment as shown in the diagram on the following page: When carrying out the experiment using this method I found that now that there was a larger area for the oxygen to go into, there wasnt much gas being collected into the glass syringe so this time I had to use more carrot gratings and hydrogen peroxide. I then, after a couple of tries to get an adequate amount of both the hydrogen peroxide and carrot gratings, determined how much of both the carrot gratings and hydrogen peroxide I needed. I found that using 5ml hydrogen peroxide to each gram of carrot gratings would give me a fairly good test. I went with using 4g of carrot gratings and 20ml hydrogen peroxide. This was going to be used as my control for the investigation. I will later add copper sulphate, which acts as an inhibitor. Also I found that I was using 1% copper sulphate solutions so I decided to use different concentrations in my investigation. I chose to use these concentrations to test inhibition: 1%, 0. 8%, 0. 6%, 0. 4%, 0. 2% and 0% as the control (with the addition of water). Finally I then decided to use 15 second time intervals to take readings on the glass syringe. I will keep doing this for approximately 3 and a half minutes.