Tuesday, October 15, 2019

Enzyme Catalysis Essay Example for Free

Enzyme Catalysis Essay Enzymes catalyze nearly all biochemical reactions in living cells (Hein, Best, Pattison, and Arena, 2005). As a catalyst, they regulate the chemical reactions by lowering the needed activation energy (Sackheim and Lehman, 1998). Catalysts facilitate chemical reaction but are not consumed, thus, can be used all over again. This function of enzymes is directly dependent on their three-dimensional structures and on the variables that affect their stereochemistry. It was believed that all enzymes are protein in nature but several findings showed that certain ribonucleic acids (RNAs) have enzymatic function (Hein et. al. , 2005). A typical organism has a thousand of biological simple or conjugated enzymes. A simple enzyme is made up of amino acid units while a conjugated one has both protein and non-protein parts that are called apoenzyme and coenzyme respectively (Hein et. al. , 2005). The substrate or substance by which the enzyme will act upon binds at the enzyme’s active site. This active site is about 1-5% of the total surface area of the enzyme (Hein et. al. , 2005). Catalysis follows that is usually describe as formation of enzyme (E) and substrate (S) complex, then, E-S complex decomposes to yield the product and the enzyme. Enzyme-catalyzed reactions are affected by several factors. This may be due to the variables effect on the stereochemistry of the enzyme and kinetics consideration. For instance, temperature affects the rate of all chemical reactions. The higher the temperature, the faster the chemical reaction takes place. However, enzymes coagulate in higher temperatures while lower temperatures results to low reaction rate. Thus, a particular enzyme best functions at its optimum temperature (Sacheim and Lehman, 1998). Concentration on the other hand, favors faster rate of chemical reaction. An increase in substrate concentration, hence, leads to a faster reaction until to the point wherein the enzyme is saturated by substrate. Moreover, every enzyme has an optimum pH range where it can function best (Sackheim and Lehman, 1998). Slight pH changes affect the polarity of the amino acid backbone of the enzyme resulting to changes in its catalytic function. In this simulation experiment, the catalytic capability of a hypothetical enzyme at different environmental conditions was investigated. The effect of temperature, pH, and substrate concentration on its optimal catalytic function were taken into consideration. In addition, the optimal temperature and optimal pH of the hypothetical enzyme were also determined. Moreover, the relationship between the enzyme concentration and the reaction rate was also explored. Procedure The spectrophotometer equipment was used in the simulation experiment in order to measure the amount of the product formed by the enzymatic reaction. The spectrophotometer is equipped with wavelength of light adjustment within 300-700 nanometre range, and percent transmittance (T) or absorption (A) of light by the sample. In addition, six different substrates labeled from A to F and six different enzymes also labeled from A to F were provided. The wavelength setting for each substrate was indicated on the vial and the clock above the substrate vials were used in setting the wavelength selector and in taking the time of the reaction respectively. Temperature, pH scale, a pipette, and a cleaning button were also made available. The substrate A and the enzyme A were used all throughout the simulation experiment. Optimal PH Five milliliter of enzyme A was added to 25 mL of substrate A and the spectrophotometer was set at 430 nanometer wavelength. This was done for every sample for 2, 4, 6, 8, and 10 pH values. The absorption for each sample was measured within one minute and 25Â ° temperature. Then, the graphical representation of data was made by plotting pH values against absorption values. Optimal Temperature Five millilitre of enzyme A was added to 25 mL of substrate A. This was done for 10Â °, 20Â °, 30Â °, 40Â °, 50Â °, 60Â °, 70Â °, and 80Â ° temperature values. The spectrophotometer was set at 430 nanometre wavelength and each sample was maintained with pH 8 value. Also, one minute absorption reading was allotted for every sample. Then, the temperature values were plotted against absorption values. Reaction Rate At this part of the simulation experiment, two mixtures of substrate A were prepared. The first sample was prepared by adding 5 mL of enzyme A into 25 mL of substrate A while the other sample was made by adding 25 mL of subtrate A with 15 mL of enzyme A. The spectrophotometer was set at 430 nanometre wavelength and the absorption reading for each sample was done for every 10 seconds within 2 minutes. The pH of each sample was maintained at pH 8 value. Finally, the graphical representation of time and absorption was made for each sample.

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