The Effect of Substrate Concentration on the Reaction of Catalase

The Effect of Substrate Concentration on the Reaction of Catalase

Sydney Moore

April 16th, 2018

Abstract

This experiment was conducted to find out if a higher concentration of substrate was added to a solution with a constant concentration of enzyme. In this case catalase was the enzyme and hydrogen peroxide (H2O 2) was the substrate. To do this, different concentrations of H2O 2 were put into a nalgene bottle and a drop of the enzyme catalase was added and then the rate of reaction was measured by a O2 pressure sensor. As the concentration of the H2O 2 increased, the slope of each line was supposed to increase. By conducting this experiment it proved our hypothesis to be incorrect.

Introduction

The purpose of this lab was to investigate enzyme activity, observing a standard reaction of catalase breaking down hydrogen peroxide, and conducting a self-designed experiment to observe the effect that the amount of catalase introduced into the solution of hydrogen peroxide has on the reaction time relative to oxygen produced. In the in class reaction lab, a gas pressure sensor was used to determine the rate of catalase activity by measuring the pressure caused by the oxygen gas that was produced. The introduction of catalase (the enzyme) into the substrate (hydrogen peroxide) causes a reaction that produces oxygen and water. The catalase that was used was Bovine catalase. In mammals catalase is usually found in the liver but it can also be used in the food industry. Catalase found within the food industry can be used to help preserve food and even make drinks from it. Commercial catalase can break down H2O 2 into wastewater. The in class experiment procedure required 10 mL of 1.5% H2O 2 in a Nalgene bottle, to which in a closed environment with the gas pressure sensor attached, 100 uL of enzyme was added. The reaction activity caused a decrease in pressure. This slope was later used to compare the effect of adding more concentration of substrate to see if it had an effect on the rate of reaction. We performed two trials with altered amounts of substrate added, to measure the effect that the quantity of substrate had on the rate of reaction, while maintaining all other variables of the experiment as used in the original. We increased the amount of substrate by going under the original, and then by ½ the original and then H2O 2 without diluting it (3%). The results produced enables us to conclude that increasing the amount of substrate introduced into 10 mL of 1.5% H2O 2, decreases the rate of reaction of the enzyme activity. The overall purpose of this investigation was to summarize what we had learned through previous activities and individual research by conducting an experiment on enzyme activity and reaction rate, and factors that affect the rate of reaction. While completing our own experimental design we concluded our hypothesis to be as substrate concentration increase the O2 emission will decrease.

Materials and Procedure

Materials include: 250 mL nalgene bottle, 4 different concentrations of H2O 2(in this experiment 0%, .75%, 1.5%, and 3% were used), safety equipment, micropipettes, graduated cylinder, Vernier gas pressure sensor, Logger Pro software, Vernier LabQuest Mini, ring stand, a computer, magnetic stirrer, stir bar and catalase concentration of 100 uL.

To replicate this experiment, follow these steps:

Put on safety equipment; including gloves, goggles and aprons

Gather all the materials that are listed above

Hook up the Vernier LabQuest Mini and the Vernier Gas Pressure Sensor together and then up to the computer that has the Logger Pro software downloaded and pulled up

Place 10 mL of 1.5% H2O 2 into a clean Nalgene bottle

Place a stir bar into the bottle

Position a magnetic stirrer on the base of the ring stand

Using a micropipette, add 100 uL of enzyme to the contents of the Nalgene bottle

Swirl contents of the bottle to ensure thorough mixing

Place O2 Gas sensor into the Nalgene bottle

Start the magnetic