Bio Lab Report On The Enviromental Effects Of Enyzyme Catzlyzed Reaction

Enzymes are a kind of protein that catalyze reactions by bonding to specifically shaped active sites thus lowering the energy reaction level which in turn speeds up the reaction. Catecholase or polyphenoloxidase (PPO), an enzyme found in various fruits and vegetables, converts catechol to benzoquinone and water in the presence of oxygen. (Mitchell et al., 2002) Fruits and vegetables use this process to protect themselves from rotting and bacteria. (Wegener, 2002)

In this experiment we focused on the effect enzyme concentration, substrate concentration, temperature, and pH, had on the enzyme activity of catecholase (in this

In Experiment 3 the rate of reaction increased with temperature until approximately 35ºC when the rate of reaction dropped dramatically. Up until that temperature range the reaction occurred at a reduced rate. After that point the high temperature denatured enzyme causing a dramatic drop in the rate of reaction. The actual optimal temperature for catechol is between 24-27 ºC (Wegener, 2002). The results of this prove for example why mashed potatoes don’t turn brown when exposed to air. As soon as the potatoes are boiled, the enzymes become denatured making it highly unlikely for the reaction to occur. Most of catecholase activity is stopped at 65 ºC. (Kaaber et al., 2002) In Experiment 4 the rate of reaction peaked at a pH of 6.6. Above and below that pH the enzyme was denatured causing the reaction to occur at a slower rate. The ruslts of Experiment 4 are due to the same reasons of Experiment 3: the enzyme becomes denatured and loses its shape. The reason for the difference in our results in relation to the true optimal of catecholase could be due to inefficient heating techniques on the experimenters behalf. Also though, mixing the tubes every minute is inefficient in the sense that you have to remove the test tube from the water bath (heating technique) causing a break in what is supposed to an uninterrupted heating process. In the future another method of keeping the contents well mixed could be used.

The corresponding graphs can be found on following page(s).

In this experiment four different environmental and concentration factors were tested and compared by taking readings of absorbance on a spectrophotometer set at 420nm (note: all readings were taken at this setting).

Some topics in this essay:
Methods Materials, Introduction Enzymes, , rate reaction, enzyme substrate, potato juice, ph 7, temperature ph, et al 2002, phosphate buffer, et al, al 2002, 1ml water, substrate concentration, 7 phosphate buffer, ph 7 phosphate, amount enzyme substrate, enzyme substrate concentrations,