ENZYMES ARE PROTEINS!
Enzymes have names that often end in the suffix
“-ase.”
FOR EXAMPLE:
LIPASE breaks down LIPIDS
MALTASE breaks down MALTOSE
PROTEASE breaks down PROTEINS
ENZYMES REACT WITH ONLY ONE (1) TYPE OF
MATERIAL. THIS IS CALLED A SUBSTRATE.
The SUBSTRATE has a SHAPE that “FITS” together with the shape of the enzyme.
THE SHAPE ON THE SURFACE OF THE ENZYME
IS CALLED THE ACTIVE SITE.
Notice that the SUBSTRATE has a shape that will
“FIT” together with the ACTIVE SITE of the ENZYME.
Together they will form an ENZYME-SUBSTRATE
COMPLEX.
ENZYME-SUBSTRATE COMPLEX
The enzyme-substrate complex is TEMPORARY.
ENZYME FUNCTION
• Enzymes control the RATE of chemical reactions. That
means that they SPEED UP the reaction WITHOUT
BEING CHANGED!
• Enzymes act as ORGANIC CATALYSTS. They lower the
amount of energy needed for a reaction to occur.
• Enzymes are NOT changed by the reaction so they
can be used over again and again and again….
LOCK AND KEY MODEL OF ENZYME ACTION
If the KEY doesn’t have a
SHAPE that FITS with the
LOCK, then it will not open
the lock.
If the ENZYME and
SUBSTRATE don’t FIT
together, a REACTION
will NOT occur.
ENZYMES DO NOT CHANGE!!
After a reaction is over, the SUBSTRATE is changed, but the ENZYME remains the same.
Notice that the
substrate was
changed at the
end of the
reaction.
A - Enzyme
B – Active Site
C - Substrate
D – Enzyme-Substrate Complex
E – Enzyme
F - Products
THERE ARE TWO (2) KINDS OF ENZYME-CONTROLLED
REACTIONS:
SYNTHESIS
(Build up)
Makes COMPLEX
substances by
joining simple
ones together
HYDROLYSIS
(Break down)
Sometimes called
DIGESTION!
Breaks complex
molecules into
smaller, simple ones
SYNTHESIS
HYDROLYSIS
HYDROLYSIS REACTION VIDEO
http://youtu.be/b7TdWLNhMtM