reaction rate and PH

Enzymes are catalysts that speed up reactions by binding to the reacting molecules. It is important to note that an enzyme can catalyze the same form of reaction multiple times. The rate of these enzymatic reactions is influenced by a number of factors. They include the PH, temperature, catalyst, and substrate reaction. The experiment will look into the influence of PH on reaction time. Hydrogen ions have an effect on the tertiary structure of enzymes. The aspect slows the reaction rate. Since the ions are reactive, they combine with charged ions, resulting in an immediate reaction. Charged ions are found in proteins such as enzymes. Therefore, their structure is affected by PH levels. At low PH, the structure of the enzymes can be denatured (World Anesthesia 4)

Hydrogen ions affect the tertiary structure of enzymes, which has a direct effect on the ability of the protein to catalyze reactions. The main aim of the experiment was conducted to conclude if the reaction rate changes in response to variation in pH levels. The experimental results indicated that at a neutral pH level the reaction rate is faster.

Methodology

Materials

Liver extract, Petri-dish, filter disk, 10% 3ml of varying levels of Hydrogen peroxide.

Procedure

The liver extract was extracted as per the instructor and mixed well. The extract was then poured into a petri-dish. 25 filters disks were then placed in the petri-dish. In the reaction chamber, four excerpts were soaked in hydrogen peroxide. The experiment was performed using 3% hydrogen peroxide with a PH of 3, followed by a PH of 5, 9 and 11. The results were then recorded in the table below.

Results

Table 3: pH Effect

PH of H2O2 Rate of O2 mL/min

3 5

5 9

7 13

9 11

11 7

A Graph showing Rate of Oxygen Production under Different PH

Discussion

Enzymes are catalysts that increase chemical reaction rates by binding to a reactant molecule. Almost all processes in a cell need proteins to occur at a significant rate. Without enzymes, life as we know it would not exist. The experiment was conducted to determine if variation in pH levels affect the reaction rate of a catalyst. Three different pH levels from acidic to primary were tested to determine if the difference in pH levels alter the tertiary structure of the protein, hence changing its function. The acidic and basic standards of pH showed the slower reaction rate of the catalyst, demonstrating that at those pH levels the tertiary structure of the enzyme has been damaged. The aspect indicates that changes in pH can have a direct effect on the ability of the protein to catalyze and supports the hypothesis that the tertiary structure, and therefore the function of catalase, is disrupted in acidic or basic solutions. As shown in the data and graph the acidic and basic pH levels had a stagnant reaction rate as opposed to the neutral ph. However, there were some discrepancies during our second trial. The fluctuation of the results in the second test was caused by a change in the procedures. For instance, we did not pour the solutions in the same matter as the first trial, and we did not change the test tubes to new dry ones. Although the discrepancies did very little to improve the results, it might have been conducted in a better more precise matter (World Anesthesia 3).

In the experiment, oxygen production is measured as a way of indicating how fast, slow or if the reaction is even occurring. In the reaction chamber, hydrogen peroxide breaks down into oxygen and water. The amount of oxygen produced is then estimated to examine the rate of the reaction. An increase in the production of oxygen indicates that the rate of reaction is a fast and low production of oxygen is an indication of the slower reaction rate. When hydrogen peroxide with a PH of 3 was used, the rate of oxygen production was 5ml/min. An increase in the PH to about five the rate also increased to 9ml/min. The aspect indicates that an increase in PH increases the rate of enzymatic reaction. At a neutral PH, the rate of oxygen production was 13ml/min. Further increase in PH to about 9 slowed the reaction rate. The aspect indicates that an increase in PH over the neutral level denatures the enzymatic structure thus slowing down the reaction rate.

Conclusion

Using the experimental results, it is clear that an increase in PH increases the rate of enzymatic reaction. It is also worth noting that at a neutral PH, the rate of reaction is at its optimum level. However further increase In PH denatures the enzymes and the rate of reaction slows down. The phenomenon indicates that enzymes function well at neural PH. The aspect is due to the fact that these enzymes are made of charged proteins in which their structure is easily affected by the introduction of hydrogen ions.

Work Cited

World Anaesthesia. February 26, 2008. Retrieved on September 4, 2009 from

http://www.nda.ox.ac.uk/wfsa/html/u13/u1312_01.htm