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Enzymes and their importance
Effect of substrate concentration on enzyme action
Importance of enzymes in our life
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The practical was carried out to investigate the effect of pH on the reaction of the enzyme acid phosphatase.
Of the many functions of proteins, catalysis is by far the most vital. When catalysis is not present, most reactions in the biological systems take place very slowly to produce at an adequate pace for metabolising organism. The catalysts that take this role are called enzymes. Enzymes are the most efficient catalysts; they can enhance rate of reaction by up to 1020 over uncatalysed reactions. (Campbell et al, 2012).
Enzyme catalysis is dependant upon factors such as concentration of enzyme and substrate, temperature and pH. These factors determine the rate of reaction, and an increase in temperature or pH above the optimum will lead to the denaturation of the enzyme and a decrease in the rate of reaction. There are many phosphatase enzymes but they are classified as those with alkaline and acid pH optimum. Both catalyse general reaction: ROPO3H2+ H2O –ROH + HPO42-+2H+.
Each enzymes works with a small range of pH, there is a pH at which its activity is greatest called optimal pH. This is due to the changes in pH can make a break intra and intermolecular bonds, distorting the shape of the enzyme, and its effectiveness. Generally, enzymes have an optimum pH this doesn’t go to say that the optimum is the same for each enzyme. For example the optimum pH for enzyme pepsin found acidic lumen in the stomach is lower than that of the enzyme carbonic anhydrase that works in the cytosol at neural pH.
Predominantly, enzymes show specificity for phosphatase monoesters but are relatively non-specific to (RO-). This can be used to construct an assay that uses non-physiological substrate, p-nitrophenyl phosphate, and one that has a p...
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...testing) would enable a clear distinction in determining the variation in the data. However, the mean can show a simple interpretation of a distorted view of distribution on occasions (outliers). Standard Deviation gives the right picture, smaller the standard deviation higher the central tendency and data is concentrated around the mean. Higher value of standard deviation indicates better distribution of data. Thus, a specific read on the optimum pH can be identified.
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References
Campbell, M.K., Shawn, S.O. (2012). Biochemistry, 7th Edition. The Behaviour of Proteins: Enzymes. Pg 139-159.
Van Etten, R.L. and Waymack, P.P. (1991). Substrate specificity and pH dependence of homogeneous wheat germ acid phosphatase. Archives of Biochemistry and Biophysics 288, 634.
Walsh, C. (1979) Enzymatic Reaction Mechanisms, W.H. Freeman, San Francisco.
The control for both curves was the beaker with 0% concentration of substrate, which produced no enzyme activity, as there were no substrate molecules for...
The purpose of this study is to analyze the activity of the enzyme, catalase, through our understanding
More hydrogen ions in a solution is a result of lower pH, while fewer hydrogen ions in a solution is a result of increased pH. Meaning that a lower pH level results in a higher enzyme activity reaction and a higher pH level results in a lower enzyme activity reaction (Christianson, 2011 ).
Finally, the last part of the experiment examined the enzyme activity at different pH levels. Four sets of 11 tubes were set up in this part. The procedure for this part is the same as before, but 4 other buffers were substituted for the standard pH 7.3 phosphate buffer. Set A used the 5.5 pH buffer while set B used the 6.5 pH buffer. The buffer of pH 8.5 was used for set B and for set D the pH was 9. The absorbance readings for 4 sets were taken and recorded in table 13. Using the linear equation that the best-fit line gave for each set, the Km and the Vmax of each set were determined. Then, table 15 was made by dividing the Vmax by the Km. of the four pHs. The Vmax and Km of the control set were also used to make
The purpose of this experiment was to determine the effects that varying temperatures, enzyme concentration, and pH had on catalase activity.
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).
Alkaline Phosphatase (APase) is an important enzyme in pre-diagnostic treatments making it an intensely studied enzyme. In order to fully understand the biochemical properties of enzymes, a kinetic explanation is essential. The kinetic assessment allows for a mechanism on how the enzyme functions. The experiment performed outlines the kinetic assessment for the purification of APase, which was purified in latter experiments through the lysis of E.coli’s bacterial cell wall. This kinetic experiment exploits the catalytic process of APase; APase catalyzes a hydrolysis reaction to produce an inorganic phosphate and alcohol via an intermediate complex.1 Using the Michaelis-Menton model for kinetic characteristics, the kinetic values of APase were found by evaluating the enzymatic rate using a paranitrophenyl phosphate (PNPP) substrate. This model uses an equation to describe enzymatic rates, by relating the
...e substances at 37.5̊C due to the fact that in the previous experiment, this was found to be the optimum temperature that catalase reacts at. It was because of this constant that I used the set of data of the catalase at 37.5̊C from the first experiment to provide a neutral environment for the experiment. The way in which the data was collected for the first experiment was identical to that needed to be done by the second. From this data, it was determined that the neutral environment for the catalase had the best results, which makes it clear that when the enzyme is in a pH of the opposite extremes such as basic or acidic, it is un able to function properly. When it is too basic then the enzyme will become inactive and when the enzyme is too acidic then the enzyme will denature, both rendering it unable to function at its optimum efficiency that all enzymes need.
Various methods such as x-ray crystallography, NMR, and site-directed mutagenesis are applied to study how AP structure contributes to its function and how cofactors and amino acid residues affect reaction mechanism. Enzymes that retain similar structure and function to E. coli AP are found in other species and organisms. For instance, the physiological functions of human AP are still not known at present, but the level of alkaline phosphatase in bloodstream can be a valuable indicator to diagnose liver and bone diseases. Also, mutation in structural gene of human AP will result in hypophosphatasia, a metabolic disease that interfere with uptake of phosphorus and calcium. Thus, understanding the functions of metal ions and reaction mechanism of E. coli AP will provide a general insight of how other enzymes work and discover future potential use of AP in different areas of research or clinical
Many factors, for example, pH and temperature affects the way enzymes work by either increasing the rate or determining the type of product produced (). The report, therefore, analyses the effects of the enzyme peroxidase in metabolic reactions and determining its optimum temperature in the reactions.
Enzymes as mentioned before help speed up reactions, they generally work by bonding to a substrate, this bonding occurs at the active site. This link then forms a different molecule which will benefit its respective process. Every enzyme has its own optimum pH level to work under, if too low the enzyme will be very slow. However if too high the enzyme will then denature and be obsolete. This is why it is important to know the optimum pH level for whatev...
From looking at the results I can conclude that when the pH was 3 and
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.
The Effect of pH on the Activity of Catalase Planning Experimental Work Secondary Resources Catalase is a type of enzyme found in different types of foods such as potatoes, apples and livers. It speeds up the disintegration of hydrogen peroxide into water because of the molecule of hydrogen peroxide (H2O2) but it remains unchanged at the end of the reaction.
I decided to experiment with pHs within the range pH 2 to pH7, as I