THE R

OLE O

F

ENZYMES

ENZYM

ES ARE “

BO

SSY”

PRO

TEINS

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

SYNTHESIS

(Build up)

Makes COMPLEX substances by joining simple ones together

HYDROLYSIS

(Break down)

Sometimes called

DIGESTION!Breaks complex

molecules into smaller, simple ones

THERE ARE TWO (2) KINDS OF ENZYME-CONTROLLED REACTIONS:

SYNTHESIS

HYDROLYSIS

HYDROLYSIS REACTION VIDEO

http://youtu.be/b7TdWLNhMtM