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Testing for enzymes

Description

Enzymes are biological catalysts, they increase the speed of a chemical reaction. They are large protein molecules and these enzymes are very specific to certain reactions.  Hydrogen peroxide decomposes slowly in light to produce oxygen and water. There is an enzyme called catalase that can speed up (catalyse) this reaction.

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
testing-for-enzymes



Apparatus Chemicals

Eye protection

Each working group will require:

Conical flasks (100 cm3), 3

Measuring cylinder (25 cm3)

Bunsen burner

Wooden splint

A bucket or bin for disposal of waste materials

Hydrogen peroxide solution, '5 volume'

Liver (small piece) (Note 1)

Potato (small piece) (Note 1)

Celery (small piece) (Note 1)

Refer to Health & Safety and Technical notes section below for additional information.

 




Some vegetarian students may wish to opt out of handling liver samples, and this should be respected.

Before or after the experiment, the term enzyme will need to be introduced. The term may have been met previously in biological topics, but the notion that they act as catalysts and increase the rate of reactions may be new. Similarly their nature as large protein molecules whose catalytic activity can be very specific to certain chemical reactions may be unfamiliar. The name catalase for the enzyme present in all these foodstuffs can be introduced.

To show the similarity between enzymes and chemical catalysts, the teacher may wish to demonstrate (or ask the class to perform as part of the class experiment) the catalytic decomposition of hydrogen peroxide solution by manganese(IV) oxide HARMFUL - see CLEAPSS Hazcard.

If students have not performed the glowing splint test for oxygen for some time, they may need reminding of how to do so by a quick demonstration by the teacher.



Enzymes are biological catalysts, they increase the speed of a chemical reaction. They are large protein molecules and these enzymes are very specific to certain reactions.  Hydrogen peroxide decomposes slowly in light to produce oxygen and water. There is an enzyme called catalase that can speed up (catalyse) this reaction.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology .