Enzyme Catalyzed Reaction Lab Report

Enzymes are biological catalysts, which means it decreases activation energy in reactions. The lower activation energy in a reaction, the faster the reaction rate. Many enzymes alter their shape when they bind to the activation site. This is called induced fit, meaning for the enzyme to work to its full potential it has to change shape to binding substrate. The location of enzyme’s activation site is on the surface of the enzyme, where the binding of substrates take place. Enzyme activity can be influenced by a variety of environmental factors. If the concentration of enzyme is low, and there is a great deal of substrate, then increasing enzyme concentration results in more molecules available to convert substrates to products. Thus, increasing enzyme concentration can increase reaction rate. If substrate concentrations are low, and many of the existing enzymes are idle because of a lack of substrate, then adding enzyme will have no effect on reaction rate. Enzyme concentration affects the enzyme activity, because the more enzyme concentration the faster the reaction rate, until it hits it’s limiting factor. When substrate concentration is increased, it also increases rate of reaction. Temperature plays an important

Used to see if the temperature of the water is at 37oc – 40oc and if

Enzyme catalysis is dependant upon factors such as concentration of enzyme and substrate, temperature and pH. These factors determine the rate of reaction, and an increase in temperature or pH above the optimum will

10 microliters of the sample is then added and the assay absorption is measured at 340nm. If absorbance was above 1.5, samples were diluted.

If the substrate concentration is increased then the rate of a catalase reaction will also increase until it reaches the optimal concentration or saturation point and will remain constant. This is because there will be more substrate molecules in a higher concentration therefore a higher frequency of collisions. This increases enzyme activity and more product will be formed. However at a certain concentration the enzymes will become saturated (all

3) Adding less enzyme caused the reaction to proceed more slowly than when more enzyme was utilized.

Substrate concentration also affects the rate of reaction as the greater the substrate concentration the faster the rate of reaction and all the active sites are filled. At this point the rate of reaction can only be increased if you add more enzymes in to make more active sites available.

What does the changes in the amount of substrate on an enzyme’s reaction effect on?

The hypothesis for substrate concentration of the experiment is that enzyme concentration rate of the enzymatic reaction increases with increasing concentration of the substrate. (Kimball)

After the substrate solution was added, five drops of the enzyme were quickly placed in tubes 3, 4 and 5. There were no drops of enzyme added in tubes 1 and 2 and in tube 6 ten drops were added. Once the enzyme solution has been added the tubes were then left to incubate for ten minutes and after five drops of DNSA solution were added to tubes 1 to 6. The tubes were then placed in a hot block at 80-90oC for five minutes. They were then taken out after the five minute period and using a 5 ml pipette, 5 ml of distilled water were added to the 6 tubes and mixed by inversion. Once everything was complete the 6 tubes were then taken to the Milton Roy Company Spectronic 21 and the absorbance of each tube was tested.

However, the rate of reaction only increases for a certain period of time until there is lesser substrate molecules than the enzyme molecules. The increase of enzyme concentration does not have effect if there are lesser substrate molecules than enzyme molecules initially.

An enzyme stock was created by crushing a Lactaid pull with a mortar and pestle and dissolving it in 10ml of 0.1M Phosphate buffer. After letting it dissolve in a beaker for a couple of minutes, the enzyme solution of Lactase isolated from Lactaid was filtered into another beaker with a small paper towel. Following filtration, 0.5ml of the stock enzyme solution was added to the 4.5ml buffer, transferring 0.5ml from one tube to the next. This serial dilution took place to determine the optimal dilution that will be used for the experiment. Phosphate buffer was used as the blank in the spectrophotometer which was set at a wavelength of 420.

The products produced by the first reaction were used as a substrate for the second. In this case the enzyme used NADH, which resulted in the decreased absorbance due to the NADH oxidation to NAD+. In addition, the spectrophotometer was used as a measuring device to follow the change in absorbance of the NADH molecules at 340nm.

As an enzyme-catalyzed reaction may be the main reason for a reaction to occur faster, many factors can

reaction rate increases. If the temperature of an enzyme gets to high the reaction rate will slow