Determining Optimal pH for Tyrosinase-Catechol Reaction Rates
Department of Biology, Swarthmore College
The environmental conditions in which an enzyme is in heavily influence the rate at which it catalyzes reactions. Tyrosinase is an enzyme common in animals and plants, and is responsible for the pigmentation of skin and browning in plants. We measured the enzymatic reaction rate of tyrosinase in pH of 4,6 and 8 by assaying catechol’s transformation into ortho-quinone and used a spectrometer to measure the absorption of light and color over time. Enzyme and substrate were independently used on the spectrometer for each pH as a control for absorption value. The data shows that the enzymatic react rate of tyrosinase, calculated using the rate of change of absorbance over time, was highest at pH 8 and lowest at 4, meaning that tyrosinase is less efficient in acidic environments.
Biological functions are supported by a variety of controlled and optimized chemical reactions. Proteins called enzymes serve as biological mediators to these chemical reactions by lowering the activation energy required for the reaction. The rate at which enzymes react is influenced by environmental factors like pH level and temperature, substrate and enzyme concentration. Therefore to optimize the speed at which biological functions essential to life occur, it is essential to understand how environmental conditions affect the activity levels of enzymes.
Tyrosinase is an