Important Cellular Enzymes

Catalase

What is it and What is it for?

• Catalase is an enzyme made in the cells of all organisms

• It is needed to break down Hydrogen Peroxide which is toxic to cells

What is Hydrogen Peroxide?

• This is made as a by product of metabolic reactions.

• Metabolic reactions involve the synthesis and breakdown of substances as well as cell respiration

• Metabolism involves many different reactions but one of the ‘waste’ products produced is Hydrogen Peroxide.

Why is it toxic to cells?

• Hydrogen Peroxide (H2O2) splits very readily into Hydroxide radicles (OH-)

• These are incredibly reactive (unstable) and will attack other substances in the cell in order to gain electrons to make themselves stable

• They are a molecule commonly called a ‘Free Radicle’

• They will break bonds of cell molecules including, carbohydrates, proteins, DNA, RNA, lipids etc

What is the Reaction of this breakdown?

What happens when H202 is added to cut apple in a test tube?

• Small bubbles form around the apple

What happens if its added to fresh ground Liver?

The solution fizzes dramatically and bubbles nearly flow over the top of the test tube

Why do the bubbles form? What are they?

• Bubbles form because the catalase is increasing the rate of the reaction

• These bubbles are oxygen gas

Why does the liver react the most? Especially the ground liver?

• One of the liver’s main jobs is the breakdown of toxic byproducts of metabolism so its cells are chock a block with catalase

• Grinding up the liver will increase its surface area and allow the catalase out of the cells more easily to react.