Determining and understanding the enzyme activity in different types of Oncorhynchus mykiss muscle (heart, white and red) by comparing rate of reaction (V) of the succinate to the substrate concentration [S] Emily Reside 0785150 Lab Section 104 January 29th 2015 Introduction Understanding the activity of enzymes in different muscle types can aid greatly in obtaining more information about other processes such as metabolism of the tissues (Anderson et al., 2012). There are many different methods in order to achieve this information based in two different major categories but the most convenient method is one called continuous assay. This process includes the use of a spectrophotometer to continuously monitor the assay. This method allows for an easy way to calculate the initial rate of reaction as one can establish time points easily. In the lab performed the continuous method was used in order to determine the measurement of the activity enzyme succinate dehydrogenase (SDH). SDH is most commonly found in mitochondria. It is present in many different muscle tissues including the heart, red, and white tissue. In the following lab the enzyme was tested and measured in these three muscle types in the Oncorhynchus mykiss in order to determine which type contained the highest and the lowest activity. This enzyme is involved in multiple processes such as involved in both the Krebs cycle and the electron transport chain (ETC) (Smith, 2014). Its role in
At five minute intervals over the next fifteen minute period, record the color intensity of the solution of each test tube.
The enzyme lactate dehydrogenase (LDH) catalyzes the last step of anaerobic glycolysis that is important for the normal function of the body. Purification of LDH is essential to understand its structure and function. The purpose of this experiment was to extract and purify LDH enzyme from chicken muscle tissue using a variety of various. Analytical methods such as activity and protein assay were employed to determine the presence and purity of LDH. The cells were initially disrupted and proteins were solubilized. LDH was purified from the ammonium sulfate precipitated protein mixture by affinity chromatography and its activity was studied by
Enzymes are types of proteins that work as a substance to help speed up a chemical reaction (Madar & Windelspecht, 104). There are three factors that help enzyme activity increase in speed. The three factors that speed up the activity of enzymes are concentration, an increase in temperature, and a preferred pH environment. Whether or not the reaction continues to move forward is not up to the enzyme, instead the reaction is dependent on a reaction’s free energy. These enzymatic reactions have reactants referred to as substrates. Enzymes do much more than create substrates; enzymes actually work with the substrate in a reaction (Madar &Windelspecht, 106). For reactions in a cell it is
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
These results shown from this experiment led us to conclude that enzymes work best at certain pH rates. For this particular enzyme, pH 7 worked best. When compared to high levels of pH, the lower levels worked better. The wrong level of pH can denature enzymes; therefore finding the right level is essential. The independent variable was the amount of pH, and the dependent being the rate of oxygen. The results are reliable as they are reinforced by the fact that enzymes typically work best at neutral pH
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.
3. Specifically state where in the intestine sucrase is likely to be most active (pH along GI tract).
We can assume any activity in the control is from enzymes besides SDH since there is no succinate, or substrate, for SDH added. By subtracting this amount from the other reactions ,we obtained a more accurate result of what SDH activity was,
Jones, A. E. & H., G., 1963. Oxidation of succinate and the control of the citric acid cycle in the mitochondria of guinea-pig liver, mammary gland and kidney. Biochemical Journal, 87(3), p. 639–648.
In this lab, I investigated aerobic respiration in the Krebs cycle through the means of a color indicator. The Krebs cycle is a vital metabolic pathway that occurs in the mitochondria and produces energy utilized by living cells. In order for the Krebs cycle to occur, glucose needs to combine with oxygen. Furthermore, in this lab, I used Malonate as an inhibitor; a competitive inhibitor binds to an enzyme’s active site inhibiting the substrate from binding which ceases the production.
Literature value states that the optimal pH of muscle LDH is at 11.5. The experimental determination of the LDH optimal pH is not too far off the literature value, in fact on figure 2, the difference between enzyme velocities between pH 10.5 and pH 11.5 is not too far off. This experimental was successful even though there is a slight deviation from literature values. Experimental errors of this experiment are most likely caused by slightly inaccurate readings of the spectrophotometer. Although a large range of pH values was tested to find the optimal pH, to improve this experiment, it would be better to lower the range of pH tested.
In the exercise # 2 we observed the effect of substrate concentration, enzyme concentration, pH and temperature on enzyme activity. All the data showed that once potato extract was added to catechol and water the reaction varied dependent on the level of catechol. As in
Protein purification is a process that can be employed to separate a single protein from a larger starting material which may be anything from an organ to a cell. Isolating a purified protein from a larger fraction enables further analysis such as determination of amino acid sequence, potential biological function, and even evolutionary relationship. (Cuatrecasas 1970) In this experiment, the enzyme lactate dehydrogenase will be purified, this enzyme is found extensively in human cells and catalyzes the conversion of lactate to pyruvate, an essential part in energy production. LDH is a key part of anaerobic energy production especially within glycolysis in which LDH catalyzes the conversion of the reverse reaction, pyruvate to lactate, generating NAD+ from NADH, reproducing the oxidized form of the coenzyme which can be used for oxidative respiration. (Markert 1963) Due to the fact that number of purification steps correlates with the purity of the protein multiple purification techniques will be used to isolate a pure form of LDH. LDH will be isolated from a larger “cytosol” fraction collected from a homogenized rat liver in a previous fractionation exercise. Of the procedures that will be used to isolate and purify proteins from a larger fractionate are a set of techniques collectively known as chromatography. These techniques all have the same premise, in that they consist of a stationary phase, also known as the
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.
Lactate dehydrogenase is an enzyme that is found in most living organisms which catalyzes the conversion of lactate to pyruvic acid. It converts NAD+ to NADH and back again. Pyruvate is converted to lactate when oxygen isn’t present and the reverse reaction takes place (Wikipedia). There are two major subunits of lactate dehydrogenase which are the M form and the H form. The M form, major subunit in muscles, is efficient in the conversion of pyruvate to lactate. The H form, major subunit in the heart, is efficient in the conversion of lactate to pyruvate. Despite the differences in structure of the M and H form, there’s enough similarity for hybrids of the M and H form to form (Goodsell).