BIOL 118 Study Guide - Microtubule, Enzyme Assay, Cheesecloth
Document Summary
The effect of enzyme concentration (ppo) on dopachrome amounts. The purpose of this laboratory was to use isolated ppo preparations from potatoes to analyze the activity of the enzyme ppo. Ppo, or polyphenol oxidase, is found in plants, fungi, and animals and leads to browning of fruits and vegetables once they have been exposed to air. Ppo also leads to the brown color in tea, coffee and cocoa; therefore, not all browning by ppo is unfavorable. It is believed that ppo leads to browning as a method for defense against infection in wounded tissues since the brown compounds from ppo may be toxic to bacteria. Dopa, also known as dihydroxypheylalanine, converts to dopaquinone in this laboratory, and then quickly changes into dopachrome, which is orange colored. In the experiment, the formation of the dopachrome product allows for the characterization of ppo in terms of enzyme kinetics.
