HOW DOES ETHYL ALCOHOL INHIBIT THE RATE OF

CATALYST ENZYME ACTIVITY?

By: Jeranika Semien

INTRODUCTION:

The general focus of this project is the study of enzymes and

how they work.

The purpose of this experiment is to determine whether or not

ethyl alcohol can inhibit the rate of catalytic enzyme activity.

The reason I choose this specific area to study was based on

the fact that I like to make this occur. Mixing chemicals and

watching them react is interesting to me, so, I choose to use a

catalyst in hopes of enhancing some kind of reaction in the liver.

BACKGROUND INFO..

Enzymes are proteins that participate in cellular

metabolic processes. The basic function of an

enzyme is to increase the rate of a reaction.

Enzymes are important because they act as

biological catalysts. This means that they bring

molecules together in such a way that they can

react.

FAST FACT

All of the reactions that they catalyze are

chemically possible (at least in theory) even in the

absence of enzymes. However, in the absence of

enzymes, these reactions could not occur fast

enough to support life.

INFO (CONT’D)

Enzymes bind temporarily to one or more of the

reactants of the reaction they catalyze. In doing so,

they lower the amount of activation energy needed

and thus speed up the reaction. Catalase is an

enzyme reactant that catalyzes the decomposition of

hydrogen peroxide into water and oxygen. One

molecule of catalase can break 40 million molecules

of hydrogen peroxide each second.

Carbonic anhydrase is found in red blood cells

where it catalyzes the reaction. It enables red blood

cells to transport carbon dioxide from the tissues to

the lungs. One molecule of carbonic anhydrase can

process one million molecules of CO2 each second.

In order to work, an enzyme must unite with at least one of

its reactants. In most cases, the forces that hold the enzyme

and its substrate are noncovalent. A noncovalent bond is a

type of chemical bond, typically between macromolecules,

that does not involve the sharing of pairs of electrons, but

rather involves more dispersed variations of electromagnetic

interactions. Four commonly mentioned types of non-

covalent interactions include hydrogen bonds, ionic bonds,

van der Waals forces, and hydrophobic interactions. The

noncovalent interactions hold together the two strands DNA

in the double helix, stabilize secondary and tertiary

structures of proteins, and enable enzyme-substrate binding

and antibody-antigen association

OTHER INHIBITORS..

There are many things that could inhibit a catalytic

reaction. Some this include temperature, pH, and

whether or not the enzymes are in competition with

one another.

HYPOTHESIS

The higher the concentration of the alcohol

solution, the slower the rate of the enzyme activity

will be.

EXPERIMENTAL DESIGN DIAGRAM

DV: The rate of the enzyme activity.

C: Same amount of liver; same amount of solution;  

IV: Different concentrations of alcohol solutions

Levels: 0% .2% .4% .6% .8%

Trials: 1 1 1 1 1

MATERIALS

Beaker Water Ethyl alcohol 6 equally cut pieces of liver Oxygen probe 100mL graduated cylinder 6 Flasks 10mL graduated cylinder Scalpel or knife Hydrogen peroxide

PROCEDURES

1. Add 90mL of water and 10mL of ethyl alcohol to a beaker. Label beaker 1% solution.

2. Add one piece of liver to a flask. 3. Once liver is added and labeled, pour in 100mL of solution.4. Measure 10mL of hydrogen peroxide and add to the flask.5. Quickly attach the oxygen probe to the flask.6. Press Start on the Logger Pro programing option.7. Give flask a final whoosh and allow it to collect data for 5 minutes. 8. Repeat steps 1 thru 7 for remaining solutions of concentration.

DATA

ANALYSIS..

The data received from this experiment varies too much to make conclusive

generalizations. I hypothesized that the concentration of the alcohol solution

was directly related to the reaction rate of the enzyme; the higher the

concentration level, the slower the reaction time will be. The data collected

from this experiment does support my hypothesis but the data varies too much

to conclude that it is accurate. The data was collect for a period of 5 minutes.

It took the .2% solution 4.75 min +/- .25 min to reach 33.01 which is the

maximum amount of oxygen that was able to be created with the given

circumstances. It took the .4% solution 3.50min +/- .25 min, .6% solution 4.75

min +/- .25 min, .8% solution 3.00 min +/- .25 min, and the 1% solution 2.25

min+/- .25 min.

LIMITATIONS

I thought that by conducting this experiment a steady correlation between

concentrations would be made. For example, as the concentration increases,

the reaction time decreases (my hypothesis) or even an opposing theory, like

as the concentration increases, the reaction time is faster. Instead, I received

what seemed to be a scatter plot of data. No exact correlation could be made.

This can be due to human errors and flaws within my experiment. Although I

tried to keep it as close to the time as possible, the time it takes to pour in the

alcohol, attach the probe, and press start on the lab pro software varied

approx. +/- 4.00 sec. Also, the measurements of the solutions may have been

off by +/- .05 mL. All of these things could have affected the array of different

figures collected.

CHANGES

One thing that I learned from conducting this experiment is that that

there are many things that can inhibit the reaction time of an enzyme.

These things include temperature and pH. In hopes of actually

attaining conclusive data, a few adjustments can be made. The first

thing I would change is the way I collected the data. Instead of using

the oxygen probe, I would use the stopper and syringe method. This

means that a stopper would be attached to the flask and the syringe to

a cord. As oxygen is formed, it would cause the syringe to move. I

would then record the oxygen displaced by reading the number on the

syringe.

WORKS CITED

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Enzymes.html

http://en.wikipedia.org/wiki/Enzyme

http://www.biology-online.org/dictionary/Catalyses

http://chemistry.about.com/od/chemistryglossary/a/reactantdef.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/oxred.html

Practice and theory of enzyme immunoassays: Volume 15 - Page 358