Enzyme concentration and enzyme activity. Trypsin

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Enzyme concentrations and enzyme activity

Purpose:

To investigate how enzyme concentration can affect the rate of reaction, in this case the breakdown of protein by protease enzyme. The protein substrate in this reaction will be trypsin milk protein (casein).

Background:

Trypsin is an endopeptidase, protease enzyme that is made in the pancreas and used to digest proteins so that the body can absorb them into the blood. The pancreatic duct in people who have cyctic fibrosis frequently becomes blocked, reducing or preventing the release of pancreatic enzyme ino the small intestine.

Enzymes are biological catalysts made up from protein that changes the speed of chemical reactions without themselves being changed at the end of the reaction.

Enzyme action occurs at the surface of the enzyme called the “active site” which has a shape complementary to the substrate, when the enzyme and substrate collide, the substrate locks into the enzyme’s active site. The active site alters its shape holding to the substrate tightly, an enzyme-substrate complex is formed in which the substrate undergoes the reaction.

Enzyme concentration:

As the enzyme concentration increases the rate of the reaction increases linearly, because there are more active sites and so the reaction can proceed at a faster rate. Eventually, increasing the enzyme concentration beyond a certain point has no effect because the substrate concentration becomes the limiting factor.

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Hypothesis:

As the enzyme-protease’s concentration increases, the time taken for the breakdown of protein will decrease, meaning the rate will increase.

The site of the reaction occurs in an area on the surface of the enzyme protease called the active site. At low enzyme concentration there is great competition for the active sites and so the rate of reaction is low. If the concentration is higher, there are more active sites, more enzyme-substrate complex is formed and so the reaction can proceed at a faster rate.

Procedure:

The experiment involves seeing what affect an enzyme trypsin ...

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*** This a basic practical write up that has obtained a set of usable data but is missing the depth and detail that would be required for an A2 coursework report. To improve Research and rationale Whilst some background knowledge is included it is expected that some research is carried out and carefully selected for inclusion to help inform the plan. Planning The variables could be considered more carefully , such as the use of a thermostatically controlled waterbath and the use of a buffer. The written method should include full details such as the source and strength of the stock solutions. Whilst the range of concentrations was adequate, it should be expected that replicates or class data are included. Implementing Some data has been recorded but the headings of the tables could be more informative. It should have been possible to get replicate data in the time available. Analysis and evaluation The graph was only partially visible so it is difficult to comment but the discussion of the results does refer to biological knowledge. It would be helpful to have seen a calculation of rate and the comparison of rates at different temperature intervals. if background research had been carried out then the actual results could have been compared to those found in the literature. The evaluation could be improved by detailing a proposed method for using the colorimeter to measure transmission.