Enzymes:
“Helper” Protein molecules
Regents Biology
2009-2010
Flow of energy through life
§  Life is built on chemical reactions
Regents Biology
Nothing works without enzymes!
§  How important are enzymes?
u 
all chemical reactions in living
organisms require enzymes to work
§  building molecules
w  synthesis enzymes
enzyme
+
§  breaking down molecules
w  digestive enzymes
live
We can’t
without enzymes!
u 
enzymes speed up reactions
§  “catalysts”
Regents Biology
enzyme
+
Enzymes are proteins
§  Each enzyme is the specific helper to
a specific reaction
each enzyme needs to be the right shape
for the job
u  enzymes are named for the reaction
they help
u 
Oh, I get it!
They end
in -ase
§  sucrase breaks down sucrose
§  proteases breakdown proteins
§  lipases breakdown lipids
§  DNA polymerase builds DNA
Regents Biology
Enzymes aren’t used up
§  Enzymes are not changed by the reaction
used only temporarily
u  re-used again for the same reaction with
other molecules
u  very little enzyme needed to help in many
reactions
u 
substrate
active site
Regents Biology
product
enzyme
It’s shape that matters!
§  Lock & Key model
u 
u 
shape of protein
allows enzyme &
substrate to fit
specific enzyme
for each specific
reaction
Regents Biology
2
1
3
Regents Biology
Enzyme vocabulary
§  Enzyme
u 
helper protein molecule
§  Substrate
u 
molecule that enzymes work on
§  Products
u 
what the enzyme helps produce from
the reaction
§  Active site
u 
part of enzyme
that substrate
molecule fits into
Regents Biology
What affects enzyme action
§ What could denature (alter)
enzymes?
§ Extreme Temperature and
§ Extreme pH (acids & bases)
Regents Biology
For enzymes…
What matters?
SHAPE!
Regents Biology
2009-2010