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Catechol Oxidase Lab

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Catechol Oxidase Lab
The Effect of Different Concentrations of the Enzyme Catechol Oxidase on the Rate of Benzoquinone Production When Mixed with Pure Catechol

Carson Levine
November 4th, 2013

Abstract

Catechol oxidase is an enzyme that speeds up the oxidation reaction when catechol is exposed to oxygen. When the reaction occurs, benzoquinone is produced turning the oxidized substance brown. It was hypothesized that the higher the concentration of catechol oxidase, the browner the substance will turn, and the faster it will achieve the color. In the present lab, different concentrations of catechol oxidase were mixed with pure catechol and the rate at which each solution browned was measured using a colorimeter. The results showed that the solution with the high concentration of catechol oxidase had the fastest rate at which it turned brown. However, it did not turn the brownest, the solution with the medium concentration of enzyme did. These results show that our hypothesis was both supported and not supported and it was concluded that increase in catechol oxidase concentration increases rate of turning brown but does not increase the level of brownness a substance becomes.

Introduction

Have you ever wondered why the inside of your apple turns brown if you leave it on the counter after taking a bite? This is because there is a compound within the apple called catechol which, when exposed to the air, becomes oxidized by the oxygen in the air and produces benzoquinone, which makes the apple appear brown (Andrew Clapper’s Online Journal, 2007). This chemical reaction is catalyzed by the enzyme catechol oxidase (Figure A.1). Enzymes are proteins in cells that speed up chemical reactions (Enzyme Procedure Guide, 2013). The catechol oxidase lowers the amount of energy needed in order for the catechol to be oxidized, which speeds the process up.

Fig. A.1: The oxidation process of catechol with the help of catechol oxidase produces

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