The Effect Of Varying Ph Values On The Enzymatic Activity Of Glucose Oxidase

Enzymes speed up metabolic reactions necessary for life. Without them certain vital processes would not take place and the body would be unable to function.

This experiment looked at how substrate concentration can affect enzyme activity. In this case the substrate was hydrogen peroxide and the enzyme was catalase. Pieces of meat providing the catalase were added to increasing concentrations of hydrogen peroxide in order to measure the effect of hydrogen peroxide concentrations on the enzyme’s activity. The variable measured was oxygen produced, as water would be too difficult to measure with basic equipment.

Introduction:Enzymes are made up of proteins which are produced within living cells and act as catalysts which speed up chemical reactions. They are made up of long chains of amino acids containing carbon, hydrogen, oxygen and nitrogen. Enzymes are structured to be

The role of an enzyme is to catalyse reactions within a cell. The enzyme present in a potato (Solanum Tuberosum) is catechol oxidase. In this experiment, the enzyme activity was tested under different temperature and pH conditions. The objective of this experiment was to determine the ideal conditions under which catechol oxidase catalyses reactions. In order to do this, catechol was catalyzed by catechol oxidase into benzoquinone at diverse temperatures and pH values. The enzyme was exposed to its new environment for 5 minutes before the absorbance of the catechol oxidase was measured at 420 nm using a spectrophotometer. The use of a spectrophotometer was crucial for the collection of data in this experiment. When exposed to hot and cold temperatures, some enzymes were found to denature causing the activity to decrease. Similarly, when the pH was too high or low, then the catechol oxidase enzyme experienced a significant decrease in activity. It can be concluded after completing this experiment that the optimal pH for catechol oxidase is 7 and that the prime temperature is 20º C. Due to the fact that the catechol oxidase was only tested under several different temperatures and pH values, it is always possible to get a more precise result by decreasing the increments between the test values. However, our experiment was able to produce accurate results as to the

Lab six requires students to observe the effects of pH and enzyme concentration on catecholase activity. Enzymes are organic catalysts that can affect the rate of a chemical reaction depending on the pH level and the concentration of the enzyme. As pH comes closer to a neutral pH the enzyme is at its greatest effectiveness. Also at the absorbance of a slope of 0.0122 the enzyme is affected greatly. The pH effect on enzymes can be tested by trying each pH level with a pH buffer of the same pH as labeled as the test tube and 1mL of potato juice, water, and catechol. This is all mixed together and put in the spectrophotometer to test how much is being absorbed at 420nm. As the effect on enzyme concentration can be tested almost the same way. This part of the exercise uses different amounts of pH 7-phosphate buffer and potato juice, and 1mL of catechol mixed together in a test tube. Each substance is put in the spectrophotometer at a wavelength set tot 420nm. The results are put down for every minute up to six minutes to see how enzyme concentration affects reaction rate. The results show that the pH 8 (0.494) affects the enzyme more than a pH of 4 (0.249), 6 (0.371), 7 (0.456), and 10 (0.126). Also the absorbance is greatest at a slope of 0.0122 with test tube C that has more effect on the reaction rate, than test tube A, B, and D.

The aim of my investigation is to see how pH affects the activity of potato tissue catalase, during the decomposition of hydrogen peroxide to produce water and oxygen.

The purpose of this investigation is to discover the effect of pH on the activity of catalase, an enzyme which plays the integral role of converting hydrogen peroxide into water and oxygen, and discover which pH level it will work at the most efficient rate (the optimum). The original hypothesis states that that the optimum would be at a pH is 7, due to the liver, where catalase usually resides, being neutral. The experiment consists of introducing the catalase to hydrogen peroxide, after exposure to certain solutions; hydrogen peroxide, water and hydrochloric acids, all containing the adjusted pH, and measuring the height of froth formed, an observable representation of the activity of the enzyme. The final data indicated that

Enzymes are biological catalysts, which accelerate the speed of chemical reactions in the body without being used up or changed in the process. Animals and plants contain enzymes which help break down fats, carbohydrates and proteins into smaller molecules the cells can use to get energy and carry out the processes that allow the plant or animal to survive. Without enzymes, most physiological processes would not take place. Hundreds of different types of enzymes are present in plant and animal cells and each is very specific in its function.

Catechol, in the presence of oxygen is oxidized by catechol oxidase to form benzoquinone (Harel et al., 1964). Bananas and potatoes contain catechol oxidase that acts on catechol which is initially colorless and converts it to brown (Harel et al., 1964). In this experiment, the effect of pH on the activity of catechol oxidase was conducted using buffers ranging from pH2 to pH10. Two trials were conducted due to the first trial results being altered by an external factor. The results were acquired by taking readings every 2 minutes for 20 minutes from a spectrophotometer and then recorded on to the table. The data collected in the table were then made into graphs to illustrate the influence of pH on the catechol oxidase catalyzed reaction. After analysis, the data revealed that pH did have a significant influence on the enzyme as recorded by absorbance per minute. However, the data was collected was not accurate due to external factors, thus the results are debatable and should be experimented again for validation.

Enzymes are a key aspect in our everyday life and are a key to sustaining life. They are biological catalysts that help speed up the rate of reactions. They do this by lowering the activation energy of chemical reactions (Biology Department, 2011).

The purpose of this experiment is to learn the effects of a certain enzyme (Peroxidase) concentration, to figure out the temperature and pH effects on Peroxidase activity and the effect of an inhibitor. The procedure includes using pH5, H202, Enzyme Extract, and Guaiacol and calibrating a spectrophotometer to determine the effect of enzyme concentration. As the experiment continues, the same reagents are used with the spectrophotometer to determine the temperature and pH effects on Peroxidase activity. Lastly, to determine the effect of an inhibitor on Peroxidase, an inhibitor is added to the extract. It was found that an increase in enzyme concentration also caused an increase in the reaction rate. The reaction rate of peroxidase increases at 40oC. Peroxidase performed the best under pH5 and declined as it became more basic. The inhibitor (Hydroxy-lamine) caused a decline in the reaction rate. The significance of this experiment is to find the optimal living conditions for Peroxidase. This enzyme is vital because it gets rid of hydrogen peroxide, which is toxic to living environments.

Abstract: Enzymes, catalytic proteins that at as catalysis which makes the process of chemical reactions more easily. There are two main factors that actually affects enzymes and their functions which are temperature and pH. Throughout this experiment, the study how pH and peroxidase affects each other and the enzyme was made. The recordings of how the enzymes responded when it was exposed to four different pH levels to come up with an optimum pH which was predicted in the hypothesis and the IRV at the end.

“Enzymes are proteins that have catalytic functions” [1], “that speed up or slow down reactions”[2], “indispensable to maintenance and activity of life”[1]. They are each very specific, and will only work when a particular substrate fits in their active site. An active site is “a region on the surface of an enzyme where the substrate binds, and where the reaction occurs”[2].

The experiments involved PH buffers of different pH were added to potato juice, water, and the enzyme catecholase. The mixture was then subjected to spectrophotometer at a wavelength of 420nm taking the absorbance readings. In the second experiment, a phosphate buffer of PH 7.0 was used in different measures together with different measurement of potato juice and the enzyme catecholase then subjected to the spectrophotometer at a wavelength of 420nm. The data collected inform of table and analyzed using descriptive statistics such as line graph and later interpreted, showing that PH and enzyme concentration do affect the rate of enzyme reaction

The purpose of this lab report is to investigate the effect of substrate concentration on enzyme activity as tested with the enzyme catalase and the substrate hydrogen peroxide at several concentrations to produce oxygen. It was assumed that an increase in hydrogen peroxide concentration would decrease the amount of time the paper circle with the enzyme catalase present on it, sowing an increase in enzyme activity. Therefore it can be hypothesised that there would be an effect on catalase activity from the increase in hydrogen peroxide concentration measured in time for the paper circle to ride to the top of the solution.