The Enzyme Catalase Experiment

The Enzyme Catalase Experiment

Aim

A series of experiments involving the enzyme Catalase has been

performed in order to determine some of the enzyme's properties. The

enzyme had its reaction rate found in different conditions. Variation

of enzyme concentration, variation of pH, variation of temperature,

and the effect of different concentrations of inhibitors were all

tested.

Increasing the enzyme concentration increased the reaction rate. An

optimum pH and temperature were found for the enzyme, outside of this

optimum the reaction rate would be lower. As inhibitor concentration

rose, the reaction rate fell.

Introduction

Virtually all of the complex biochemical reactions that take place in

animals, plants, and micro organisms are regulated by enzymes. Most

enzymes are Proteins. Each enzyme is able to catalyse only one type

(or a small number) of chemical reactions. Enzymes may only catalyse

reactions which can happen naturally; the substrates do not require

the enzyme but the reaction is much faster in its presence.

In 1965 a theory was created by biologists describing an 'induced fit'

- where the structure of an enzyme is altered by its substrate, by the

movement of charges and hydrophobic/hydrophilic interactions, so the

substrate fits perfectly on the active site in such a way that its

reaction can be catalysed. Once the reaction has ended, the enzyme

returns to its original shape which uses up the least energy to hold

together. It was the work by chemists on the strong and weak chemical

bonds which allowed for this theory to be created. Catalase was

discovered to produce this induced fit in the presence of Hydrogen

Peroxide.

Catalase promotes the breakdown of Hydrogen Peroxide (H2O2) into

non-harmful products, Water and Oxygen by the equation:

CATALASE

2H2O2 ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯>2H2O + O2

Model of catalase structure

As can be seen in the diagram, the Catalase molecule is a very complex

protein. Its structure is held together by a variety of bonds