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How Amylase Concentration Affects the Rate of the Starch Concentration
In this piece of coursework, I have to carry out an investigation to
find out how amylase concentration affects the rate of starch. Enzymes
are biological catalysts that speed up the chemical reaction that goes
on inside living things. An enzyme acts on substrate and may do its
job inside or outside the cells.
However, the rate at which enzymes work are affected by the following
factors/variables:
Concentration: In a more concentrated solution, collision occurs more
often because there are more molecules. The more often these molecules
collide, the greater the chance they having of reacting. This means
that the rate of a chemical reaction will increase if the
concentration of reactants is increased.
However, in this experiment, I'm going to do an investigation to find
out how amylase concentration affects the rate of starch
Hypothesis:
In this investigation, the concentration of enzyme will be inversely
proportional to the time taken for starch to be digested, until at a
certain point where it will level out. It will level out because, all
the substrates would have been used up, therefore there will be no
more substrates for the enzymes to work on. In effect, the
concentration of the substrate will act as a limiting factor. However,
enzyme concentration will be directly proportional to the rate of
reaction.
The independent variable for this experiment is the enzyme
concentration, and the range chosen is from 1% to 5% with the
measurements of 1, 2, 4, and 5%. The dependant variable to be measured
is the absorbance of the absorbance of the solution within a
colorimeter,
Equipments:
Iodine solution: used to test for present of starch - Amylase solution
- 1% starch solution - 1 pipette - 3 syringes -
8 test tubes – Stop clock - Water bath at 37oc - Distilled water-
colorimeter
Method:
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Amylase is an enzyme found in our bodies, which digest starch into
Data from Table 1. confirms the theory that as the concentration of glucose increases so will the absorbance of the solution when examined with the glucose oxidase/horseradish peroxidase assay. Glucose within the context of this assay is determined by the amount of ferricyanide, determined by absornace, which is produced in a one to one ratio.1 Furthermore when examining the glucose standards, a linear calibration curve was able to be produced (shown as Figure 1). Noted the R2 value of the y = 1.808x - 0.0125 trend line is 0.9958, which is statistically considered linear. From this calibration curve the absorbance values of unknowns samples can be compared, and the correlated glucose concentration can then be approximated.
To begin the study, I first calculated how much of each solution I would need. I knew that the final volume of my reaction solution needed to me 30ml, so I calculated how much of starch, amylase, and tris buffer I would need. I used the formula Concentration (initial stock solution) x Volume (initial stock solution)= Concentration (final solution) x Volume (final solution). Using this formula, I found that I would need an initial concentration of 21 ml of starch, 1 ml of amylase, and 8 ml of the tris buffer. After calculating the amounts of substances I would need, I created two different solutions, one with the Carb Cutter and one without. Carb Cutter claims to block starch, however, to find this I needed to test the absorbance level of the control to compare the effect Carb Cutter had on the solution. Below is a graph showing the concentration of the control reaction over one minute intervals through the
For example, substrate concentration, enzyme concentration, and temperature could all be factors that affected the chemical reactions in our experiment. The concentration of substrate, in this case, would not have an affect on how the bovine liver catalase and the yeast would react. The reason why is because in both instances, the substrate (hydrogen peroxide) concentration was 1.5%. Therefore, the hydrogen peroxide would saturate the enzyme and produce the maximum rate of the chemical reaction. The other factor that could affect the rate of reaction is enzyme concentration. Evidently, higher concentrations of catalase in the bovine liver produced faster reactions, and the opposite occurs for lower concentrations of catalase. More enzymes in the catalase solution would collide with the hydrogen peroxide substrate. However, the yeast would react slower than the 400 U/mL solution, but faster than the 40 U/mL. Based on this evidence, I would conclude that the yeast has a higher enzyme concentration than 40 U/mL, but lower than 400
This evidence alone suggests that higher increases in substrate concentration causes smaller and smaller increases in enzyme activity. As substrate concentration increases further, some substrate molecules may have to wait for an active site to become empty as they are already occupied with a substrate molecule. So, the rate of the reaction starts to level off resulting in a plateau in the graphs. This means that the reaction is already working at its maximum rate, and will continue working at that rate until all substrates are broken down. The only way the reaction rate would increase, is if more enzyme was added to the solution. This confirms that increases in substrate concentration above the optimum does not lead to greater enzyme activity. Therefore, the rate of reaction is in proportion to the substrate
Overall, as the concentration of the substrate increases, the enzyme activity increases up to a 70% of solution, where the enzyme activity starts to level off. The curve is polynomial because of the fact that the enzyme activity exponentially increases as the concentration of substrate increase; additional evidence for this is the fact that the gradient graph is constantly changing. The polynomial curve is shown because until 70% (the saturation point); this is because there are more casein substrate molecules that can successfully collide with the renin enzyme molecule, therefore increasing the rate of reaction.
called an active site. This active site is made by a few of the amino
It is important however to note that the NH4 and K ions are still in
This experiment requires four tubes with an enzyme solution, chelating agent and deionized water. Also a fifth tube that is the calibration tube for the spectrophotometer, which only has 5ml of dH2O. The calibration tube is used to level out the spectrophotometer to zero before each trial. The spectrophotometer was set at 540 nm, “since green is not a color seen with the conversion of catechol to benzoquinone.” The enzyme solution was made by using potato that was peeled so that the golden color of the skin wouldn’t react or interfere with the red color needed in the spectrophotometer. After it was peeled, it was cut into chunks to minimize excess heat created while it was blended. It was put in a chilled blender and 500ml of deionized water was added. Chilled, deionized water was used because it created a hypotonic environment that caused the cells from the potato to burst and release the catecholase. It was chilled
Abstract: Enzymes are catalysts therefore we can state that they work to start a reaction or speed it up. The chemical transformed due to the enzyme (catalase) is known as the substrate. In this lab the chemical used was hydrogen peroxide because it can be broken down by catalase. The substrate in this lab would be hydrogen peroxide and the enzymes used will be catalase which is found in both potatoes and liver. This substrate will fill the active sites on the enzyme and the reaction will vary based on the concentration of both and the different factors in the experiment. Students placed either liver or potatoes in test tubes with the substrate and observed them at different temperatures as well as with different concentrations of the substrate. Upon reviewing observations, it can be concluded that liver contains the greater amount of catalase as its rates of reaction were greater than that of the potato.
Investigating the Effect of Substrate Concentration on Catalase Reaction. Planning -Aim : The aim of the experiment is to examine how the concentration of the substrate (Hydrogen Peroxide, H2O2) affects the rate of reaction. the enzyme (catalase).
I blanked it with 2 cm³ water, 1 cm³ amylase and 3 drops of iodine.
The [ES] complex can then undergo two different pathways; the complex can dissociate to [E] and [S], at a rate of k or it can shift equilibrium to the left with a rate constant of k2 to form [E] and product [P]1. In this model, the breakdown of the ES complex to yield P is the overall rate-limiting step. Three assumptions of a Michaelis-Menton plot are that a specific [ES] complex in rapid equilibrium between [E] and [S] is a necessary intermediate, the amount of substrate is more than the amount of enzyme so the [S] remains constant, and that this plot follows steady state assumptions. Steady state assumptions states that the intermediate stays the same concentration even if the starting materials and products are constantly changing.2 The rapid equilibrium between enzyme and substrate, and the enzyme-substrate complex yields a mathematical description regarded as the Michaelis-Menton
Gareth Williams Background knowledge (facts): Chemicals changed by enzymes catalysed reactions are called the substrate of the enzyme they fit into the active site of the enzyme; this is where the reaction takes place, this happens with a lock and key mechanism. The product of the reaction then leaves the active site, freeing it up for more similar reactions to take place. Amylase is a carbohydrase enzyme which is in our saliva gland, this helps digest the carbohydrates that we eat e.g. pasta and bread etc. [IMAGE] Starch is a large molecule which is made up of lots of other smaller
How the Concentration of the Substrate Affects the Reaction in the Catalase Inside Potato Cells
Investigating the Effect of Enzyme Concentration on the Hydrolysis of Starch with Amylase Aim: Investigate the effect of enzyme concentration on the rate of an enzyme-controlled reaction. Using amylase and starch as my example. Introduction: I am investigating the effect of the concentration of the enzyme, amylase on the time taken for the enzyme to fully breakdown the substrate, starch to a sugar solution. The varied variable will be the concentration and all other variables are going to be fixed. The different concentrations will be: 0.5% 0.75% 1.0% 1.5% 2% An enzyme is a class of protein, which acts as a biological catalyst to speed up the rate of reaction with its substrates.