I am going to be carrying out aliterature review about enzymes, and then talk about 5 different experimentsthat could be done for enzymes for temperature and then I will place thereferences below my work.
With enzymes, they are very vigoroustherefore it can increase the rate of reaction without it being used up withina chemical reaction, the only way in which an enzyme catalysed reaction happensis if the substrate molecule goes with the active site of an enzyme moleculewhich will then create an enzyme substrate complex. Enzymes are proteins: theyare tertiary globular proteins, which are folded in complicated shapes thatlets the small molecules to go into it and the place where the substratemolecules fit into is named the active site. There are high temperature valueswhich its activity is the greatest being the optimum temperature.The picture that I placed below displayshow this does work. In this picture 2 molecules that are tiny have connected tomake a much larger one. If the shape of the enzyme does change the active sitemay not work meaning the enzyme has denatured.
How enzymes can be denatured isby high temperatures. The reason as to why this happens is because if thetemperature get too high the enzyme will lose its three dimensional shape. Different enzymes work at differenttemperatures.
There are many enzymes in the body that have a certain role to dofor example, no matter what type of food we consume our diets are made ofthings such as: carbohydrates fats plus proteins, and what breaks down thesecarbohydrates, proteins and fats into smaller components are digestive enzymes.The enzymes optimum temperature is where thehighest rate of reaction occurs the highest temperature in which enzymes maywork in the human body is usually around 37. The Lock-and-key HypothesisThishypothesis is how the enzyme catalyse substrate reaction, the figure of theactive site match to the form of the substrate. When this moleculebumps into the enzymes active site that is matching, a substrate shall liftinto the active site and then there will be an enzyme substrate complex.Whatcatalyses the reaction is the enzyme, also what will create an enzyme product complexis the enzyme and products being catalysed by the enzyme. · The Induced-Fit HypothesisI the induced fit hypothesis, the shape of theactive site are not that complementary, but change shape in the presence of acertain substrate to become complementary. When a substrate molecule goes into an enzyme, andits arrangement is correct, the shape of the enzymes active site does change sothat the substrate will fit into it then an enzyme substrate complex is formed,this reaction is then catalysed and an enzyme product complex can be formed. TemperatureAn enzyme will eventually denature if thetemperature gets too high, as this will cause the enzymes weak bonds that keepsit together to separate therefore the structure of it will change, this happensmostly around 50-60 degrees.
Denatured enzymes do not work the image below showsthe relationship between temperature and enzyme activity. Inhibitors Withinhibitors, it does slow down the reaction taking place when the substrate is connectingwith the active site of an enzyme. Thiscould be either non- changeable or changeable inhibitors, and with thischangeable inhibitor it can be either competitive or non-competitive. With a competitive inhibitor, it can connect to the activesite of an enzyme, this is because it has a shape that is like the substrate,therefore this will prevent the substrate from connecting with the active site. Non-competitiveinhibitors do not bind to the active site, therefore the substrate cant bindthe active site below is a comparison diagram: With the pH it’sa measure of the concertation of pH+ ions up against the OH- ions, so it iseither negatively or positively charged and has a high or low pH can change theenzymes function, every single enzyme has an optimal pH in which it works atits best, this being different to different enzymes, for example a lot ofenzymes work best at a pH of 7.35 pepsin with the stomach does work best a a pHof 3. Substrateconcentration When allenzymes are working all the time, adding more substrate won’t increase the rateof reaction unless more enzymes are added.
The higher asubstrate concentration is, the rate of reaction will be faster, and this iswhen all the active sites are filled so from this point to increase the rate ofreaction is only to add more enzymes. The effect of temperature on enzyme reaction: · What will be needed is : · Three percent diastase · One percent starch solution · Iodine solution · Dropping pipettes · Syringes · Stop block · Test tubes · Test tube racks · Water baths · Masking tape · Stirrers In a water put both tubes in it for aroundtwo, minutes. Placethe diastase to the starch solution them ix this and start your stop watch,write down when your solution became colourless.
At the temperature 20,30,35,40 and 50 repeatthis at all of these temperatures. Place 5 millimetres of a percent of starchinto a test tube and put two drops of iodine solution.In another test tube place 4 millimetres ofdiastase enzyme in it.
The effect of temperature on enzyme reaction:The enzyme reaction will take place with fivedifferent temperatures, firstly what will happen is you will run a reaction atthe temperatures you are going to be using with e3nzyme and one reaction being30 degrees without enzyme for a sum of 6 reactions.Label the 6 tubes, place 2 drops of latticeacid and 2 drops of PMS/INT/NAD, and 2 drops of buffer to the tubes. Into tube#1 add 2 drops of water, make sure before this you have the timer and apippete, make sure to go quickly and make sure you are adding the enzymeproperly, and putting these tubes in the water bath. Then time this reaction after 4 minutesexamine these tubes as different colours will appear and write down thedifferent colours that came up. The effect of temperature on enzyme reaction: Place20 cm of a buffer to a graduated cylinderWith a dropper add a drop of washing up liquidThe place 5 grams of chopped radish to thiscylinder Place 2 cm cubed of hydrogen peroxide to theboiling tube Put the cylinder up and the boiling tube in awater bath that is ice cold until the wanted temperature is reached Put hydrogen peroxide in the cylinder Write down the volume within the cylinder.Read the volume again after a measured amountof time then subtract the volume you got in the beginning from your finalvolume to get the volume of foam. Redo this procedure from step 3 for at thevery least 4 more temperatures to include a sample in the 50 to 60 degreerange.
The effect of temperature on enzyme reaction: Fresh catalase solution 20% Hydrogen peroxide solution Water baths 10 mL graduated cylinder teat dropper Boiling tubes that are the same but different. Stop watch ProcedureFirstly you must label all 8 of your testtubes with each temperature and the other 8 test tube from hydrogen peroxideand with its temperature, then put these boiling tubed in the test tube rack.Place a drop of catalase enzyme within acatalase tube this being labelled 0oC.Then place1mL of hydrogen peroxide in to thetube for hydrogen peroxide making sure to label it 0oC.
Put the 2 boiling tubes in the 0oC water bathfor around 10, minutes to allow for the equilibrium of temperature. Place hydrogen peroxide to catalyse then beginthe stop watch. Then measure the column of bubble after 35seconds and record this.Then repeat step 2-6 from the othertemperatures. The effect of temperature onenzyme reaction:A water bath needs to heated up to 25 degrees5 cm cubed of 4 percent casein solution has tobe placed in a test tube plus 5 cm cubed of 0.
5 percent trypsin must be addedto another tube.Then put both in a water bath until it goes tothe right temperature required,Then the same quantity of casein solution mustbe placed into another test tube and five cm cubed distilled water in a fourthtest tube. Then in the last test tube you have put 5 cmcubed of distilled water in the fifth test tube plus 5 cm cubed of casein inthe last test tube. This must all be put in a water bath.
The effect of temperature onenzyme reaction:Make sure to place asticker on the test tube you are examining and label it.Put five drips of phenolphthaleinwithin this test tubeUsing a measuring cylinder get up to 5cm cubed of the milk properly,then put it in the test tube.Then use another measuring cylinder where you will now, get up to 7mcubed of sodium carbonate, once again place it into the test tube then the solutionshall turn into the colour of pink. Make sure to place a thermometer within the test tube to check to temperature.Make sure to place the test tube within a water bath, and allow thecontents within it to react till it is the same temperature as the water bathitself. Change the thermometer that is inside the test tube to a glass rod.
Measure around 1cm cubed of the lipase with the use of an 2c cubedsyringe, from the beaker in the bath of water for the temperature that you areexamining. Begin your stop watch when you have put the lipase within the testtube. So that this solution loses the pink colour that it had what youneed to do is mix up the content in the test tube. Write down the time after you have stopped the stopwatch. 1st method: this experiment is easyto carry out because not a lot of steps are required to finish this experiment,also the person who is doing this experiment does not have to do anycalculations so this experiment is time affective.
An error can occur in thisexperiment as if the person were to put more than 2 drops of iodine in it byaccident it could affect the results they have obtained. Iodine is carcinogenic therefore it could cause cancer, and if this goes into thepersons eye it can make them blind therefore the person must fully the safetyrules when using these equipment’s and if they don’t these risks may happen tothe person doing the experiment. 2nd method: The advantage to thisexperiment is that it isn’t time consuming as it is very quick however in thisexperiment some errors could occur for instance: if the timer was not workingthe person could have gotten different results therefore the colour that wasobtained may have been wrong, if more than 2 drops of buffer was added to thetubes then once again the results obtained could be inaccurate, also anotherdisadvantage could be that this experiment can be subjective as one person maysee blue and another person my see purple instead.3rd method The disadvantage to thistest is that if the hydrogen peroxide were to be inhaled it ca affect the bodyand or if it were to come into contact with the persons eyes or skin, andadvantage to this experiment is that it is not time consuming if it were to bedone properly without any errors for example: placing more than 2cm cubed ofhydrogen peroxide in the boiling tube. 4thmetod: An error that could occurin this experiment could be that the timing may be inaccurate if the personwasn’t looking at the stop watch properly, this could also be a time consumingexperiment as you have to repeat step 2-6 for the other temperatures, andadvantage of this experiment however is the method is easy to follow. 5th experiment: You ca repeat this experiment manytimes if errors occur which is an advantage.
I f the person doing this teststudies different temperatures on different days for the same investigation,the action of the enzyme will change plus it won’t be a fair test, also theglass water is breakable so if it were to break then the person doing thisexperiment may have to repeat this whole experiment or get a new beaker whichis a waste of money. Out of all 5 methods the best one has to bethe second experiment as it is the mosttime effective compared to all of the other 4 methods and if an error doesoccur it is a repeatable experiment, and if the safety procedures are followedproperly in this experiment no risks will occur.