Enzymes
Aldolase
LN # 4
insulin-degrading enzyme
What is an enzyme?
Enzymes are very important molecules in
biology.
Enzymes are proteins that help to speed
up chemical reactions in the body.
Without enzymes, many of the important
processes of life could not happen.
Enzymes
Enzymes are very specific in their function.
Each enzyme has only one reaction that it
can help.
Enzymes are not changed when they
perform their function.
This means that the same enzyme molecule
can be used over and over again.
How do enzymes work?
 As with all proteins, the
shape of an enzyme is
what determines its
function.
 Enzymes have an active
site for the substrate.
 Substrate is changed into
a product.
http://www.tvdsb.on.ca/westmin/science/sbi3a1/digest/enzymes.htm
Starch to glucose
Active
site
Substrate
Enzyme
Product
Enzyme unchanged.
Can be reused.
Enzymes in Human Body
Amylase is an enzyme that breaks starch
down into sugar.
Amylase is present in human saliva, where
it begins the chemical process of
digestion.
Foods that contain much starch but little sugar,
such as rice and potato, taste slightly sweet as
they are chewed because amylase turns some
of their starch into sugar in the mouth
pH, Temperature and Ionic conditions
 Most human enzymes are most effective at 35°
to 40°C (close to our normal body temperature)
 Very few enzymes will work in extremely salty
solutions.
 The best conditions for most enzymes is close to
neutral, pH of 6 to 8.
 Acid rain
entire lakes are threatened by acid rain.
acid rain makes the water so acidic that the organisms
living in lakes have enzyme failure.
Summary
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What is an enzyme?
Why are enzymes important?
How do enzymes work?
What is a substrate?
What is the active site?
What is a product?
What is amylase?
What conditions can effect enzyme function?