The Effect of Different Concentrations of a Substrate On an Enzyme

The Effect of Different Concentrations of a Substrate On an Enzyme

Introduction:

Enzymes are biological catalysts. They are generally large proteins

made up of several hundred amino acids. Enzymes catalyze thousands of

chemical reactions that occur in living cells. Enzymes are highly

specific so each one speeds up only one particular chemical reaction.

Many kinds of enzymes are found in each cell but because they are used

over and over there may be only a small amount of each enzyme

present.

In this lab activity, you will study the enzyme catalase and its

substrate hydrogen peroxide. Catalase accelerates the breakdown of

hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2). The

chemical equation for this reaction is:

2 H2O2 ----Catalase-------> 2H2O + O2

Catalase is found in both plant and animal tissues. It is especially

abundant in plant storage organs such as potatoes and the fleshy parts

of fruits. Catalase is extremely important in cells because it

prevents the accumulation of hydrogen peroxide. Hydrogen peroxide is

a strong oxidizing agent, which tends to disrupt the delicate balance

of cell chemistry. If too much hydrogen peroxide accumulates, it will

kill the cell.

Several factors affect the action of enzymes: salt concentration, pH,

temperature, enzyme poisons, radiation, the concentration of enzymes,

and the concentration of the substrate.

This lab deals only with how an enzyme is affected by different

concentrations of substrate - specifically, what effect will different

concentrations of a substrate (H2O2) have on an enzyme (catalase in

potato juice).

Objectives:

1. You will determine how different concentrations of a substrate

affect the enzymatic activity of the

enzyme catalase.

2. You will construct and interpret a graph of the data collected.

Safety Notes:

1. Hydrogen peroxide can damage your clothes. Rinse any spills with

water immediately.

2. Keep hydrogen peroxide out of your eyes.