A&P 120
Enzyme Function
Exercise 4
www.celltech.com/resources/vt/enzymes.html
Terminology
• Metabolism
– Definition: The sum total of all biochemical activity that
takes place in a living organism
• Catabolic Metabolism – break down
– AB = A & B
• Anabolic Metabolism – build up
– A + B = AB
• In vitro – out of the body (or in a tube)
– In Vivo – in the body
• Substrate - The material being acted upon
Introduction
• Enzyme – a protein that is a organic catalyst
– Hint: Most of the time ends in –ase
• Catalyst – speeds up the rate of a reaction
– Catalase – is the name of an enzyme in your body
• Active Site – a pocket at the outside of the enzyme
specific to a substrate (here is where it is taken apart or put together)
Bubbles
H2O2
Catalase
2H2O2
Catalase
(organic)
2H2O +O2
(Hydrogen peroxide)
(Water & Oxygen)
Substrate
Product
H2O2
**Oxygen will bubble in vitro**
Catalase
p. 35?
Temperature
-cold temperatures inhibit (prevent) enzyme activity
-hot temperatures denature enzymes
High activity
Denature: enzyme
unravels/unfolds and
loses structure and
function
Extreme
heat
Low activity
COLD
HOT
Best
temperature
Normal
enzyme
Denature
d enzyme
p. 35?
pH = 0
Acidic –less
than 7
pH
Neutral = 7
Basic (alkaline) –
greater than 7
pH = 14
Enzymes have a
certain pH at
which they work
best
-above or below
optimum pH
inhibits activity
How Enzymes Work
• Biological Catalysis (usually proteins) – Make a reaction faster
• Enzymes are Proteins – built to work “active site”
• Proteins are Happy’ist in their natural Temp and pH
–
–
–
–
Usually ~370C or 980F & Usually a neutral pH (Function)
What would happen if you boil it? Guesses -___________
What would happen if you put it in acid? ________________
What would happen in the cold?________________
• Enzymes can only work so fast……..
– If you keep adding substrate will the
speed of the Rxn
a)
H2O2
•Poison
What does cyanide do?
Arsenic?
O2 & H2O
b)
or
Catalase
Catalase
How Enzymes Work
• Biological Catalysis (usually proteins) – Make a reaction faster
• Enzymes are Proteins – built to work “active site”
• Proteins are Happy’ist in their natural Temp and pH
–
–
–
–
Usually ~370C or 980F & Usually a neutral pH (Function)
What would happen if you boil it? Guesses -____denature________
What would happen if you put it in acid? _______denature_________
What would happen in the cold?________inhibit________
• Enzymes can only work so fast……..
– If you keep adding substrate will the
speed of the Rxn
a)
H2O2
•Poison
What does cyanide do?
Arsenic?
O2 & H2O
b)
or
Catalase
Catalase