Catecholase, Enzymatic Browning and Temperature
Title: (Please come up with something that is related with the effect of temperature and the measure of absorbance with the enzyme catecholase found in potato).
Abstract: (at least 125 words)
Introduction: (at least 250 words or more)
Materials and Methods:
Literature Cited: 5 sources from pubmed.com (Free full text) about catecholase
1. Reduced polyphenol oxidase gene expression and enzymatic browning in potato (Solanum tuberusom) with artificial microRNA’s.
2.Purification and characterization of polyphenol oxidase from fresh ginseng.
3. Extraction of Rice Bran extract and some factors affecting its inhibition of polyphenol oxidase activity and browning in potato. (I hope you can access to this article otherwise you can select your preferred article from pubmed.com that talks about enzymatic browning and temperature)
This is our laboratory experiment:
Hypothesis: If the solution of potato extract and de-ionized water and catechol is heated to 4 different temperatures, as the temperature increases, then the absorbance and reaction increases until the enzyme denature.
3 large test tubes (for hot water bath incubation)
separate 1 ml pipettes for potato extract, catechol, and water
1 ml pipette pump for 1 ml pipette
bottle of deionized water
Vernier colorimeter connected to LabQuest and set to 470nm wavelength
50 ml of 0.05% catechol
50 ml potato extract made by blending
129.6 g of potato (strained) in
500 ml of deionized H2O.
Hot plate/dish? (Heating apparatus for the boiling temp)
Exercise 1 : Rate of product formation in an enzyme-catalyzed reaction
Cuvette Potato extract(ml) Deionized H2O (ml) Catechol (ml) Color
B 1.0 2.0 0.0 Light pink
C 1.0 1.0 1.0 Darker pink
Note: Cuvette B is the reagent blank. Reagent required to observe the catecholase catalyzed reaction
We measured the rate of reaction in absorbance over time. I did not include the details because graph is not needed for this Exercise.
Measuring the absorbance through colorimeter attached to Vernier LabQuest. From 10 seconds up to 100 seconds
Temperature Cuvette B Cuvette C Time (seconds)
Room Temperature 0 0.196 70
40 degrees 0 0.633 70
60 degrees C 0 0.525 70
Boiling 100 degrees C 0 0.216 70
Please make a graph for this one.
X axis will be temperature and Y axis will be the absorbance base on the table given
Please use “according to and then name of the author instead of (“quote and in-text citation?”) per instructors wishes and translate it in your own words. This applies for all sources.
Heres a segment from my textbook that, you might be able to use some important point that I would like you to incorporate in the paper in your own words.
Increasing the temperature of an catalyzed reaction increases its rate because the additional heat increases random molecular movement. This movement can add stress to molecular bonds and the affect the activation energy of a reaction. The rate of an enzyme –catalyzed reaction also increases with temperature, but only up to a point called the optimum temperature. Below this temperature, the hydrogen bond and hydrophobic interactions that determine the enzymes shape are not flexible enough to permit the induce fit that is optimum for catalysis. Above the optimum temperature, these forces are too weak to maintain the enzyme’s shape against the increased random movement of the atoms in the enzyme. At higher temperatures, the enzyme denatures. Most human enzymes have an optimum temperature between 35 Degrees Celsius and 40 degrees C – a range that includes normal body temperature.
Things that happen during the experiment and thing we can improve in the future:
• We were delayed for 10’s in pressing the button from the colorimeter that is the reason our time is based on 70 second instead of 60.
• To have a stop watch would be handy next time
• To be more familiar with LabQuest manual to have an accurate result.