Lab on Enzymatic Activity

Safety Precautions

Practice collecting and analyzing data.
Focus on the enzyme-substrate hypothesis model.
- Enzymes and substrates interact to lower activation energy.
- Investigate how various conditions affect reaction rates.
Write a lab report on findings over the next two weeks.

Enzymes are proteins made up of amino acids.
- Primary structure: order of amino acids, determined by DNA.
- Secondary structure: folds into beta-pleated sheets or alpha helices.
- Tertiary structure: further folding of secondary structures.
- Quaternary structure: combination of multiple tertiary structures.
Enzymes have active sites specific to substrates.
- Binding causes conformational change in enzyme shape.
- Catalase enzyme and hydrogen peroxide substrate will be studied.

Found in peroxisomes.
- Breaks down hydrogen peroxide, a by-product of fatty acid metabolism.
- Converts it into water and oxygen gas.
Role of enzymes:
- Bind substrates and lower activation energy.
- Stress bonds or orient substrates for reaction.
- Enzymes remain unchanged post-reaction.
Catalase:
- Composed of four polypeptide chains.
- Converts millions of peroxide molecules into water and oxygen per second.

Use a pressure probe attached to a cork.
Mix peroxide with yeast (model organism like human cells).
- Yeast has a nucleus and organelles similar to human cells.
- Contains catalase.
Record pressure change rate.
Investigate effects of:
- Substrate concentration.
- Temperature.
- pH.

Test effects of temperature on reaction rate.
Room temperature as control.
Temperature range: up to 60°C (biologically relevant limit).
Methods:
- Incubate yeast and peroxide at different temperatures.
- Use temperature probes and thermometers.
- Stagger incubation times.