Enzymes
- Remember they are PROTEINS!
-They are ORGANIC CATALYSTS!
ORGANIC = IN LIVING ORGANISMS
-A Catalyst speeds up CHEMICAL REACTIONS
-A Catalyst does not get used up in the reaction
(it can be recovered at the end of a reaction)
- A Catalyst is needed in small amounts (because
it can be recycled!)
ENZYMES
ARE
RESPONSIBLE
FOR
SPEEDING UP
ALL
REACTIONS
IN YOUR
BODY!
 Chemical reactions  Reactants (called as ‘Substrates’ in Enzyme
catalysed reactions) are: C6H12O6 and 6O2
 Products are: 6CO2 and 6H2O
C6H12O6 + 6O2 -> 6CO2 + 6H2O
 How does an enzyme work?
How does an Enzyme Work?
 Substrates are the reactants of an enzyme
catalyzed reaction
 Substrates have a matching shape that fits into
the enzyme like a LOCK AND KEY
 A bond is formed/broken between the
Substrates and the Products are released
 Enzyme is recycled so new substrates can react
and form new products over and over again
 Enzymes are Specific to substrate
 Enzymes lower Activation Energy*
 Activation energy: Energy needed by reactants to make
the products (Energy Barrier)
 Enzymes are Organic Catalysts that can LOWER this
ACTIVATION ENERGY
A single molecule of enzyme can catalyze 1000’s of reactions
Enzymes: Factors affecting their
function
Temperature very cold = no reaction;
warm temp = fastest reaction;
cooking = no reaction
Optimal temp: Human enzymes – 37.5 oc
3) pH –
Enzymes: Factors affecting their
function
pH (Acid - ex. HCl can harm enzyme
or Base - ex. NaOH also can harm enzyme)
pH
1-6 Acidic
7= neutral
8-14 - Basic
Optimal pH: Human enzymes – pH 6-8
Enzymes: Factors affecting their
function
Coenzymes – organic helpers - Vitamin B
Examples:vitamins.
Enzymes: Factors affecting their
function
Cofactors – inorganic helpers. Ex Metals
Photosystem I
multienzyme
complexes
Inorganic Catalyst
 Inorganic - Found in ‘Nonliving’ things Example: Manganese Dioxide (MnO2)
 Inorganic Catalysts are able to be
RECYCLED just like ENZYMES
 They also speed up reaction
 They can be recovered at the end of a
reaction
Balanced Equation for the break
down of Hydrogen Peroxide:
Hydrogen peroxide
2H2O2
2H2O2
Magnanese
dioxide
Catalase
Catalyst
water & oxygen gas
2H2O + O2
(inorganic)
2H2O + O2
(organic)
Results
Add these results to the LEFT SIDE
of the data table
1.
2.
3.
4.
5.
6.
7.
N/R
F
M
M
M
N/R
F
8. M-F
9. N/R -cooked
10. F- warm
11. S- iced
12. F- dH2O,pH =7
13. M-S base, pH=10
14. S- acid, pH=3
Clean UP- 5pts of lab
 Dump Test Tube contents onto a paper towel
 Dump into the garbage can at front door
 Return unused liver and H2O2
 Rinse test tubes in sink then scrub test tubes
in soapy bin, then rinse in sink again
 NO LIVER IN THE SINK!!!!!
 Turn test tube upside down into test tube rack
to dry
 Clean the glass cutting board, razor blade,
forcepts and stir rod.