Enzymes as Tools
Enzymes are proteins that act as catalysts in the production of chemicals needed by cells. Catalysts increase the rate at which chemical reactions go to equilibrium while not being consumed in the reactions themselves. In one sense, cells can be thought of as bags of biochemical pathways in which numerous chemical reactions are all running continuously with each step in each pathway being catalyzed by enzymes. Because of the arrangement of enzymes and a continuous supply of energy to cells, chemical reactions in cells do not reach equilibrium as long as the cell is living. Cells in a state of equilibrium are called “dead” by highly trained scientists.
Enzymes act as tools for doing the work of cells, but there is nothing to stop enzymes from being used as tools to do work for us. In this very simple exercise, we will look at the difference enzymes can make in a simple everyday product, laundry detergent. Many difficult to remove fabric stains are composed primarily of proteins. Protein stains are not necessarily easy to get out using surfactants like Sodium Dodecyl Sulphate (SDS). Protelytic enzymes in detergents break up proteins and thus make those found in stains easier to remove from fabrics.
Procedure:
Day 1 - Setup
- Separate into groups of no less than three and no more than four. Do the rest of this exercise as a group.
- Take a hard-boiled egg and cut it in quarters.
- Discard the yolk
- Put 100 ml of water into each of 4 beakers.
- Add 2 ml enzyme containing detergent to one beaker, 2 ml enzyme lacking detergent to another beaker and leave the third beaker without detergent.
- The how you use the fourth beaker is up to you. You may want to try a different concentration of detergent, or a mixture of both detergents. Be as creative as you can be within the very narrow restraints of this exercise.
- Place 1/4 of the egg white into each beaker.
- Clearly mark each beaker, then let them stand at room temperature for 2 days.
Day 2 - Data collection
- Compare the egg whites in each beaker. Record this data.
- Cleanup the beakers, then start work on your lab report.
Questions you will want to address in your lab report:
What is the hypothesis you are testing in this experiment?
Which beakers acted as controls in this experiment?
Did the enzymes present in the enzyme containing detergent make a difference to the egg white?
Do the results of this experiment prove that enzyme containing detergents are better at cleaning fabrics than regular detergents?
Would you want to use protelytic enzyme containing detergent on silk fabric?
What other uses might there be for protelytic enzymes?
Why do cells make protelytic enzymes?
Materials:
- Detergent containing enzymes
- Detergent that lacks enzymes
- Water
- 100 ml Beakers (4 per group)
- Boiled Eggs (1 per group)
- Kitchen knives