Expermintal Report on Enzyme Action

Topics: Enzyme, PH, Chemical reaction Pages: 7 (1852 words) Published: May 19, 2013
Experimental Report on Enzyme Action


In this report I will be investigating how the temperature can affect the activity of the protease enzyme. We will be using 2mls of water, 30 drops of protease and photographic film will act as the substrate. The pigments used in photographic film are held onto the backing plastic by gelatine. Gelatin is a protein that the protease should break down to leave a clear backing sheet. I will be testing the enzyme and rate of reaction by placing 4 test tubes containing water, protease and the piece film in water baths, each at different temperature, and one at room temperature. The 5 temperatures we will be testing will be 20°c, 30°c, 40°c, 50°c and 60°c. We will be able to tell when the reaction has started to occur as the water in the tube will start to become cloudy. This is how we will measure the rate of reaction.

An enzyme is a protein and is a catalyst to chemical reactions.   It helps accelerate reactions by lowering the activation energy, which is needed for reactions in cells to progress at a higher rate.   Activation energy is the minimum amount of energy needed for a chemical reaction to occur, yielding products from a given set of reactants. Products are results of an enzyme cleaving to a specific substrate, by means of an induced fit.   The induced fit is located at the active site of the enzyme or region of the enzyme where the substrate is bound.   The substrate is the reactant within the reaction that fits with the enzyme like a key into a lock. Once the substrate enters the enzyme’s active site the enzyme can flexibly change shape to more snugly bind, via the induced fit,   to form an enzyme-substrate complex.   The substrate is then metabolized or broken down, resulting in a product, which can be utilized to energize cells.   Once the product is released from the active site the enzyme returns to it’s original form.

Enzymes are proteins that speed up chemical reactions in cells. They break down molecules called substrates. Each enzyme has only one substrate that it breaks down. Enzymes are produced in the cells of the body and affect the rate of almost all the chemical reactions which take place in living organisms. The rate of enzyme activity is influenced by temperature, pH, and the presence of inhibitors. Catalyse is an enzyme which is produced by every cell to break down hydrogen peroxide. Hydrogen peroxide is a waste product of cellular activity that is poisonous to cells. Catalyse speeds up the decomposition of hydrogen peroxide into harmless water and oxygen gas. The purpose of this experiment was to determine whether an inhibitor affects the rate of reaction for the enzyme catalyse. Since catalyse speeds up the production of oxygen gas, the rate of enzyme activity can be measured as the height of the column of oxygen gas bubbles produced in a test tube. Temperature affects the rate of reaction as a higher temperature is often known to speed up the reaction rate. Extreme temperatures causes the native folded structure of proteins to uncoil into random configuration. As a result, the protein loses its biological enzymatic activity. This is known as "denaturization" of a protein. PH can also affect enzymes When pH of a particular medium changes, it leads to alteration in the shape of the enzyme. Not only on enzymes, the pH level may also affect the charge properties and shape of the substrate. Within a narrow pH range, changes in the structural shapes of the enzymes and substrates may be reversible. But for a significant change in pH levels, the enzyme and the substrate may undergo denaturation. In such cases, they cannot identify each other. Consequently, there will be no reaction as such. This is the reason why pH can affect enzyme activity.

Experiment One
Hypothesis/ prediction/ aim
The aim of this experiment is to determine weather temperature had an effect on the enzyme and the rate of reaction. I predict that the higher the...
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