ENZYMES
Ms. Mezzetti
Biology
Lynn English High School
Modified from: Enzymes & Your Body
By Malinda Pires
Explain the role of enzymes as catalysts that
lower the activation energy of biochemical
reactions.
Identify factors, such as pH and temperature,
which have an effect on enzymes
Enzymes, which are a
types of proteins, speed
up chemical reactions.
Enzymes are catalysts
to over 4000 biochemical
reactions!
http://en.wikipedia.org/wiki/File:GLO1_Homo_sapiens_small_fast.gif
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Enzymes work by lowering the activation energy
needed to start a chemical reaction.
http://en.wikipedia.org/wiki/File:Activation_energy.svg
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College
Enzymes are reusable
molecules found in
living things.
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College
Take the name of the
substrate the enzyme works
on and add the suffix -ase
Example: Lactose  Lactase
Sucrose  Sucrase
Not always the case-some
enzymes end in ‘zyme
Catalase acts by breaking
down H2O2
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College
Enzymes can form to the shape of its
substrate.
http://en.wikipedia.org/wiki/File:Induced_fit_diagram.svg
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College
When an enzyme is denatured it is
damaged.
Denaturing changes the shape.
Without the correct shape enzymes
won’t function properly.
HOW are enzymes denatured?
Temperature
pH
amount of substrate or salt
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College
Chemicals that prevent the enzyme from working.
Inhibitors decrease the enzyme reaction rate.
Chemicals that help the enzyme work.
Activators increase the enzyme reaction rate.
Active
Site
Activator
X
Binding
Site
Substrate
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College
http://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Major_digestive_enzymes.png/750px-Major_digestive_enzymes.png
Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College