PP 2
enzymes
Define…
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Enzyme: a protein that functions as a biological
catalyst
Catalyst: A substance that speeds up a chemical
reaction and is not changed by the reaction. Can be
repeatedly used
Youtube on enzymes:
http://www.youtube.com/watch?v=CZD5xsOKres
Parts of enzymatic activity
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Metabolic reactions – chemical reactions that take
place in an organism for various purposes such as
respiration, digestion, photosynthesis.
Many enzymes exist for different purposes with
very specific reactions
Parts of an enzyme / lock and key
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The dent where all the
activity happens is
called the ACTIVE SITE
SUBSTRATE is what the
enzyme is working on
The PRODUCT is the
new substance is made Here the enzyme is making a
new molecule from 2 smaller
ones
Enzymes continued
Here the enzyme
is breaking
A big molecule to
make 2
Small ones (not
shown)
Lock and key model
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The enzyme is the lock and the substrate(s) is the
key. The ‘key’ must fit perfectly in the ‘lock’ for the
‘door’ (enzymatic reaction) to ‘open’ (create a new
product)
Temperature and pH effects Enzyme
Activity
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Enzymes only work when conditions are prefect for
them.
Different enzymes have different perfect conditions
They are all dependent on certain factors like
Temperature and pH.
If the enzyme looses it’s shape – it looses its activity
When the shape of the enzyme is lost – this is called
DENATURING.
An enzyme can be denatured by temperature and pH
if they are not OPTIMUM (perfect) for that particular
enzyme.
Effects of Temperature
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Bonds between molecules move faster when
temperature rises.
But if the temperature becomes too high – the
Rate of reaction vs. temp
enzyme denatures
(egg white  egg white cooked)
(Liquid / opaque  solid / white)
(Albumin  denatured protein)
Rate of reaction nearly doubles
near 400C.
Enzyme has denaturing as the
temperature increases
Effects of pH
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Effects of pH can often be reversible if
the pH is not too extreme
Optimal pH
– pH 6 - 8 for most enzymes.
– pH of 2 for stomach enzymes
Optimum temperature/ PH
Place
Optimum temperature
(Degrees Centigrade)
Inside our bodies
40
In Plants
25
Bacteria in hot spring
70
Location of Enzyme
Optimum pH
Name of enzyme
In stomach
2
Pepsin (protease – breaks
down protein)
In Mouth
7
Amylase (breaks down
carbohydrates)
pH: 0 , 1 , 2 , 3, 4, 5, 6,
Low pH
I-----------Acid----------------I
7,
8, 9, 10, 11, 12, 13, 14
High pH
Neutral I----------------Base----------------I
Role of Enzymes in…..
Germination of Seeds
Biological Washing
Products
Food industry (eg.
Pectinase)
• When seeds germinate
Amylase (enzyme) is
secreted to breakdown
carbohydrate (insoluble)
into maltose (soluble) to
break down to glucose.
•Glucose is needed for
energy for growth and
making cellulose for cell
walls.
•Helps get rid of biological
protein stains like blood,
egg yolk.
• BIOLOGICAL WASHING
POWDER
• Eg. Trypsin (enzyme)
breaks these protein down
to smaller parts called
amino acids.
•The amino acids then
dissolve in water and are
washed away.
•Eg. Lipase (enzyme)
breaks down grease
•Pectinase is added to crush
fruit for making juice so
that the juice can be
squeezed easier – it breaks
down what holds the cell
walls together.
• Makes apple juice clear
from cloudy
• Lactase breaks down
lactose for who are lactose
intolerant into glucose and
galactose.
•This is to make lactose free
milk.
Role of Enzymes
Germination of Seeds
Biological Washing
Products
Food industry (eg.
Pectinase)
Carbohydrate + Amylase
-> maltose
Protein + Trypsin
-> amino acids
Fruit + Pectinase ->
Broken down cell walls of
fruit
Grease + Lipase
-> broken down fats
Lactose + Lacatase
-> Glucose + Galactose
Outline of use of microorganisms / fermenters to make
penicillin /
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We can use microorganisms like bacteria / fungus
to make the enzyme or antibiotics that we want.
These microorganisms are made in a fermenter
Penicillin (antibiotic) can be made in a fermenter.
Antibiotic is a substance that is made by a type of
fungus called Penicillim to kill harmful bacteria.
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The fungus is grown in Medium (liquid with nutrients)
inside the fermenter and all that it needs to grow
(oxygen, carbohydrates (sugar/starch) , Nitrogen,
appropriate temperature &pH)
The fermenter is constantly stirred and cooled to
keep the temperature constant.
enzymes for washing powers
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Microorganisms that live in very high temperatures
are isolated (from hot springs)
85 Deg. C or higher is their optimal temp.
They are grown in fermeter like Penicillum
The liquid these microorganisms make is isolated
and purified for use.
The liquid contains the needed enzyme.