Apple Experiment
Come down and get a slice of apple and a slice of
lemon.
When you get back to your seat:
1. Take a bite of one side of your apple.
2. Immediately squeeze lemon juice over the apple flesh that is now
exposed from the bite.
3. IMPORTANT! Don’t get lemon juice all over the apple. Make sure
that it is ONLY on the area that you just bit!
4. Set the lemon aside and wipe any lemon juice off of your hands
with a napkin.
5. Take another bite from the opposite side of your apple slice.
6. Set your apple aside.
What Are Enzymes?
• Enzymes are
__________ (tertiary
and quaternary
structures).
• An enzyme is a
_________ in cellular
reactions.
• A catalyst accelerates
a reaction.
Enzymes
• Are ________ for
what they will catalyze
• Are _________
• End in -_____
-Sucrase
-Lactase
-Maltase
How do enzymes work?
• Each enzyme has a unique 3-D shape, including a surface groove
called an ______ _____.
• The enzyme works by binding a specific chemical reactant
(_________) to its active site, causing the substrate to
become unstable and react.
• The resulting __________ is then released from the active
site.
How Do Enzymes Work?
Enzymes work by
_______ ______
which ________
activation energy.
Enzyme-Substrate Complex
The substance
(reactant) an
enzyme acts on is
the _________.
Substrate
Joins
Enzyme
______ _____
• A specific region of an enzyme molecule which binds
to the substrate.
Active
Site
Substrate
Enzyme
Shape of a Protein
…A job well done
• An enzyme fits
with its
substrate like a
____ and ____.
EnzymeAnimation : Gary E. Kaiser http://student.ccbcmd.edu/biotutorials/proteins/enzsub.html
View : http://highered.mcgraw-
hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html
Enzymes are ____ ________ in the reactions they catalyze.
Think of them as tiny machines in manufacturing.
The more machines, the faster you get more _________.
Image:
Wine Bottling : www.morrison-chs.com/timingscrews/index.html
Wine Vats: www.lymebaywinery.co.uk/pages/about_us.htm
Formats for writing a chemical reaction.
( ________ )
_______ + ________ -----------> _________
( ________ )
__________ -----------> ______ + ______
4 levels of Protein Structure
How Do You Stop
an Enzyme?
_______________
• Changing of protein shape through
some form of external stress
• A denatured
protein can’t carry out
its function because it is a different
shape!
Factors Affecting Enzyme Activity
• Temperature
• pH
• Cofactors & Coenzymes
• Inhibitors
Temperature & pH
• Think about what kind of cell or organism an
enzyme may work in…
• Temperatures far above the normal range
_________ enzymes (This is why very high fevers are so
dangerous. They can cook the body’s proteins)
• Most enzymes work best near __________ pH
(6 to 8).
Coenzymes & Cofactors
• Non-protein substances
(zinc, iron, copper, vitamins)
are sometimes needed for
proper enzymatic activity.
• Coenzyme versus Cofactor:
What’s the difference?
_________ more general
term. Includes inorganic and
organic molecules.
_________ type of
Cofactor, But specifically
organic molecules.
Image:
EnzymeCofactor : Public domain Wiki, Ribbon-diagram showing carbonic anhydrase II. The grey
sphere is the zinc cofactor in the active site.
Coenzyme : Vitamin B12
• Example:
Most _________ are
coenzymes essential in
helping move atoms between
molecules in the formation of
carbohydrates, fats, and
proteins.
• Exclusively synthesized by
___________ (found
primarily in meat, eggs and
dairy products).
Image: VitaminB12 : NIH, Public Domain
www.nlm.nih.gov/.../ency/imagepages/19516.htm
Two Types of Enzyme Inhibitors
1. ___________ ____________:
Chemicals that resemble an enzyme’s
normal substrate and compete with it for
the active site.
Substrate
Competitive inhibitor
Enzyme
1. Competitive inhibitors:
Resemble an enzyme’s normal substrate and compete
with it for the active site.
Image: Competitive Inhibition : wwwbiol.paisley.ac.uk/.../chapter3_2.html
Two Types of Enzyme Inhibitors
_______________ ______________:
Do not enter the active site, but bind to another
part of the enzyme causing the enzyme to change
its shape, altering the active site.
Substrate
active site
altered
Enzyme
Noncompetitive
Inhibitor
Enzyme Inhibitors
Blocking an enzyme's
activity can kill a
pathogen or correct a
metabolic imbalance.
Many _____ are enzyme
inhibitors.
Enzymes are also used
as _________ and
__________.
Images
Dead Bug : www.kansas.gov/help_center/user_testing.html
Prescription Drugs : www.patentdocs.us/.../08/by-kevin-e-noon.html
Featured Enzyme #1: Catecholase
• Catecholase is present in most ______ and __________.
• It is the enzyme that facilitates the ________ of cut or
bruised fruits and vegetables by catalyzing the following
reaction:
(______________)
_________ + _____ ----------------- _____________
colorless substrate
brown product
Featured Enzyme #1:
Catecholase
& Noncompetetive Inhibition
_________ juice and other acids are
used to preserve color in fruit,
particularly apples, by lowering the ____
and removing the copper site (cofactor)
necessary for the enzyme to function.
catechol
colorless substrate
+ O2
catecholase
--------------------------
polyphenol
brown product
Featured enzyme #2: Bromelain
•
Pineapple contains enzyme bromelain, which can
_______ _________.
•
Jell-O is made of gelatin, a processed version of a
structural protein called _________ that is found in
many animals, including humans.
•
Collagen big, fibrous molecule makes skin, bones, and
tendons both strong and elastic.
•
Gelatin you eat in Jell-O comes from the collagen in
cow or pig bones, hooves, and connective tissues.
(Yummie!)
•
Examine 2 containers:
a. In one, cooked pineapple was used to make jello.
b. The other, uncooked pineapple was used.
Key to Blanks
P2: protein, catalyst
P3: specific, reusable, ase
P4: actice site, substrate, product
P5: weakening bonds, lowers
P6: Substrate
P7: active site
P8: lock, key
P10: not consumed, product
P11: reactant, reactant, enzyme, product, reactant, enzyme, product, product
P13: denaturation
P15: denature, neutral
P16: cofactor, coenzyme
P17: vitamins, bacteria
P18: competitive inhibitors
P20: noncompetitive inhibitors
P21: drugs, pesticides, herbicides
P22: fruits, vegetables, browning, catechol, oxygen, catecholase, polyphenol
P23: lemon, pH
P24: digest protein, collagen