Most people choose hydrogen peroxide over rubbing alcohol to clean a wound since hydrogen peroxide doesn’t burn. However, when hydrogen peroxide is treated on deeper wounds into the flesh, it can pose numerous problems to cellular health. When hydrogen peroxide is used correctly to clean wounds, it becomes an oxidizer and can be used as a disinfectant to prevent infections. However when used incorrectly, hydrogen peroxide can cause oxidative stress on cells. This essentially means that there is an imbalance on molecules containing oxygen and the cell cannot detoxify the products.
This creates free radicals such as hydroxyl radical that will damage all components of the cell, ultimately killing it (Tucker, 2012). However, humans actually produce hydrogen peroxide after enzymes break down certain molecules. It is not toxic when humans produce it because it is stored in peroxisomes which contain catalase that break down the hydrogen peroxide before it becomes toxic. Many oxidation and reduction reactions take place in the cell, but it is not harmful because it is balanced (Cross, n. ).
Catalase plays a significant role in minimizing the toxic substances in our body because it is an enzyme that converts hydrogen peroxide into water and oxygen gas. Without the additional input of hydrogen peroxide, the human body is well adapted to any threats substances may pose. In part A, the results demonstrated that when enzyme concentration increased, the rate of reaction also increased. This can be observed by looking at the values in table 2. 0 and the trendline on grade 2. 0.
The trendline displays a positive slope, thus dictating a positive relationship between catalase concentration and the rate of reaction. This means when catalase concentration increases, the rate of reaction also increases. In other words, at 20% catalase concentration, the rate of reaction was only 4. 220 mm/s while at 100% catalase concentration, the rate of reaction was 7. 704 mm/s. This proves the positive correlation between catalase concentration and the rate of reaction. This occurs because as the enzyme concentration increases, there are more enzymes available to catalyze substrates.
More enzymes means more reactions can take place at a time, thus a faster rate of reaction. Overall, based on the results of table 2. 0 and graph 2. 0, it is prevalent that there is a positive correlation between the concentration of enzymes and the rate of reaction. The 0% catalase reaction rate is misleading because even when the enzyme concentration is zero, it does not mean that a reaction is not taking place. The function of enzymes is to decrease the activation energy that occurs when a reaction takes place.
By decreasing the activation energy, less energy and time is wasted. Without an enzyme, the activation energy would be much higher as there is no assistance, compared to a reaction with a biological catalyst. A reaction still can take place due to the kinetic energy of the molecules, as the move and bump into each other, there is a likelier chance that a spontaneous reaction will occur. The 0% catalase reaction rate is also misleading because based on the data, the rate is unavailable as the filter paper disk never rose to the top in a span of 1. minutes. If data collection continued, the filter disk may have risen at an unknown point of time due to spontaneous exergonic reactions. The results in part B demonstrate a decrease in the rate of reaction of 80% catalase in 3% H202 + 10% CuSO4 in comparison to the rate of reaction in 80% catalase in 3% hydrogen peroxide. In table 3. 0 and graph 3. 0, it is shown that a rate of 9. 397 mm/s occurs in 80% catalase in 3% hydrogen peroxide and a rate of 4. 270 mm/s occurs in 80% catalase in 3% hydrogen peroxide and 10% copper I sulphate.
The rate of reaction in the 3% hydrogen peroxide alone is more than double than the rate of reaction in the copper II sulphate solution. This shows that the copper II sulphate causes the rate of reaction to slow down. This would mean that copper II sulphate is a non-competitive inhibitor of catalase, thus slowing down the reaction. It is non-competitive, meaning an allosteric inhibitor, because if it were a competitive inhibitor, the enzyme concentration would not affect the rate of reaction.
An allosteric inhibitor attaches onto the allosteric active site, causing the enzyme to change shape, making it dysfunctional since the substrate can no longer fit into the enzyme’s active site. This slows down the rate of reaction because there are less available enzymes to catalyze the substrate. A reaction still takes place because the concentration of copper Il sulphate is small and also due to spontaneous reactions. In conclusion, copper II sulphate acts as an allosteric inhibitor to catalase, thus slowing down the rate of reaction.
Catalase activity can also be affected by acidic and basic ions or compounds because enzymes are proteins. If they are placed in an environment that is too acidic or basic, the secondary, tertiary and quaternary structure of the protein will be damaged, and thus denature. The optimum pH level for catalase is 7, thus it will denature in any environment that is too acidic or too basic (Introduction to Enzymes, n. d). When catalase denatures, it can no longer function thus it will decrease the rate of catalase activity dramatically.
The presence of NaCl, or salt, will also affect the rate of catalase activity. A salt concentration that is too high or too low will ultimately denature the enzyme, thus permanently stopping the enzyme from working (What Factors Affect the Activities of Catalase? n. d). As a result, the rate of reaction will also decrease significantly. However, the results from the copper II sulphate reaction will not be as dramatic as changing the pH level or increasing salt concentration. The results I obtained is decent in terms of accuracy as measuring time and distance cannot be 100% accurate.
This is shown in table 2. 0 and graph 2. 0 and the points and values on the graph do not increase at equal intervals. For example, at 100% catalase, the rate of reaction is 7. 704 mm/s. However, the fastest rate of reaction is not at 100% catalase concentration as predicted, but at 80% enzyme concentration in which the rate of reaction is 9. 397 mm/s, the highest out of the data collected. It is also not as accurate because at 0% catalase concentration, the rate of reaction was listed as undetermined.
Based on my knowledge of enzymes and exergonic reactions, I know that eventually, the filter paper disk would have risen due to spontaneous reactions due to the movement of particles. An experimental error that may have affected my result may be the state of the catalase stock solution. As stated in the materials instruction on the lab, the enzyme must be kept on ice at all times, which refers to the enzyme’s optimum temperature at which it reacts. During the lab, the catalase would have cooled down by the end of the lab, thus reducing its effectiveness and impacting the final results in part B.
This issue could be mitigated by cooling down the enzyme between part A and part B. Another experimental error may be due to the transparency of the 3% hydrogen peroxide and 10% copper sulphate solution. Since the solution was transparent, I could not accurately measure the distance or time. The time and distance is not accurate as we could not measure or time correctly, thus giving an inaccurate result. This could be prevented by using a test tube to drop the filter disk in, thus creating a less opaque colour. This would allow us to measure and time the disk’s movement more accurately.
Higher catalase concentration in cells could boost longevity because since catalase prevents hydrogen peroxide from being a free radical, less cells would be damaged. Hydrogen peroxide is a damaging oxidizing agent that will increase the rate of degeneration in cells. Antioxidants, a substance that inhibits oxidation such as catalase, will decrease the damaging factor of hydrogen peroxide, thus lessening the rate of degeneration in cells. An increase in antioxidants such as catalase will also increase free radical defenses. This can lesson age-related disease such as cardiovascular disease, cancer and other chronic conditions (Rahman, 2007).