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Effect of temperature on effectiveness on the Enzyme Pectinase

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Effect of temperature on effectiveness on the Enzyme Pectinase BIOLOGY Aim The aim of the investigation is to find out at which temperature most juice extraction will take place. This will be achieved by the assistance of enzyme Pectinase. Hypothesis I predict that the grated apple, which is placed in a test-tube, that is exposed to most appropriate temperatures (temperatures that range closest to the enzymes optimum) shall have the most juice extracted from it. This is due to various reasons, ranging from the enzyme's structure (shape), it's properties and it's size. The reason as to why the enzyme's structure affects the grated apple is classic, if we were to use enzyme amylase for example, the enzyme will not affect the rate of juice extraction by a lot because although it can catalyse the apple, it isn't as well suited to the job as the pectinase enzyme is. So it's important that we use the enzyme pectinase. Enzymes are globular proteins. They have complex tertiary and often quaternary structure in which polypeptides are folded around each other to form a roughly spherical, or globular shape. The overall 3-Dimensional shape of an enzyme molecule is very important: if it is altered, the enzyme cannot bind to its substrate and so cannot function. Hydrogen bonds, ionic forces and disulphide bridges maintain the shape of an enzyme, and it is when their functions are affected by changes in temperature that we refer to the denaturing of an enzyme. ...read more.


Of course, the velocity at which the enzymes vibrate cannot be calculated at this level, but because we have enzyme in solution we can weigh the enzymes weight. The effect of temperature on a reaction can be expressed by the temperature coefficient, commonly known as Q10. Where t is the chosen temperature, the formula for the Q10 is: Rate of reaction at t + 100C Rate of reaction at t Up to about 370C, the rate of enzyme-controlled reactions increases with temperature. The optimum temperature for enzyme pectinase is about 370C, although the activity of the enzyme may increase up to about 400C or beyond. However, as the temperature passes 380C-400C, enzyme pectinase begins to lose its rate of activity. Optimum temperature 0 37 47 Temperature 0C Referring back to temperature co-efficiency, all enzymes have the same Q10 values. This variation is important because enzymes, even those in the same pathway, can vary significantly in their sensitivity to temperature. *Enzyme B *Enzyme A * * * * * * * Temperature 0C This graph illustrates the different purposes of the enzyme. How it lowers the activation energy, how it speed up chemical reactions and up to which point does it stop working as quickly due to too extreme conditions. Here it is clearly shown where the enzyme isn't functioning well yet not denatured. After the optimum the enzyme produces more or less a symmetrical pattern to the behaviour before the optimum, but at this point we know that the enzyme isn't at it's usual state and that it is beginning to break up and denature. ...read more.


This graph shows what I predict the outcome of the enzyme against temperature reaction to be. Enzyme's Optimum The blue dashed line divides the graph into it's simplest definable parts: The first half shows the rate of reaction against temperature. The enzyme activity is increasing. The other half shows the enzyme denaturing, yet enzyme activity is occurring, but at a decreasing rate. Variables Variables shall be the temperatures that the enzyme solution and grated apple will be placed in, for all the tests. All other paraphernalia shall be kept constant such as: Concentration of enzyme solution, volume of enzyme solution and amount (weight) of grated apple. Risk Assessment Of course the most important things to take into account are health and safety, so to make my experiment more professional and reach standard demands of health and safety regulations it's important that I use goggles and use tissue to wipe up any spillages and any breakages that occur during the experiments. Also, it's important to be wary of your organisation and the experiment must be laid in a 'easy accessible' manner. Lastly Preliminary work I believe that after doing the preliminary I have a better idea on how I can produce better results, hence: carry out a better and more efficient experiment (in terms of efficiency I can carry out an experiment that is more organised and one that will give results more quicker). I now know what I am expecting and to meet these demands I must perform the experiment with care and observe any changes that might happen: giving me anomalous results. ...read more.

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