Download How do Enzymes work?

How do Enzymes work?
Enzymes are known to be globular
proteins, even though they might contain
some non-protein components, they are
considered and known to be proteins.
All chemical reactions in all living
organisms require enzymes to
function; actually, no existing reaction can
take place without an enzyme. They have
the principal function of being biological
catalysts (speed up reactions), but they
also work as being synthesis enzymes
(building reactions) and digestive enzymes
(breaking down reactions). The shape of
the protein is the most important feature
in order to conduct the reaction, they have to have a specific shape,
depending upon what amino acids are joined and in what order. The
way an enzyme is shaped is known as the active site (active clef).
All enzymes have different and specific shapes
depending upon the shape their substrate has, this
helps their individual substrate to fit in perfectly with
the shape of the enzyme. The enzyme and the
substrate together are known as the EnzymeSubstrate Complex.
When the subtracts are close together in the enzyme,
their actually energy to perform their reaction can
reduce itself, therefore the reaction takes place.
Without the enzymes present, subtracts wouldn’t be able to even
collide together and there wouldn’t be a reaction at all.
There is a variation of theory’s, which describe the formation of these
enzymes.
1) Lock and Key: A molecule with a complementary
shape can fit into an active site, with call these
molecules substrates. This process is basically the
one I mentioned above, but this time I’m going to
describe it with more detail. These substrate
molecules form temporary bonds with amino acids to
produce an enzyme-substrate complex. When the
reaction has taken place the products are released,
leaving the enzyme unchanged, and able to react
again if necessary. The substrate is often described
as the key and the enzyme as the lock, which fit
together perfectly, this is known as the Lock and Key
Theory.
2) Induced fit Theory: Active sites are often known as flexible. This
method consists of the substrate entering the active site and the
enzyme molecule being forced to modify its shape, in order for it to fit
more closely to around the substrate. Only a specific substrate is able
to induce the change in the shape of an enzymes active site.
We have to take in mind that once the substrates have reacted
together, the enzymes release them. This is known as the product of
the reaction. But Enzymes are not changed by this reaction, they
aren’t used up, once the products leave, the enzyme can be used
again for the same reaction with more of the same substrate.
Some reactions can bring substrates together and make them react to
make a complex product. These are known as Synthesis reactions.
Other reactions bring a complex into the active site and break it down
into two or more products, this is known as a Degradation/digestion
reaction.
Synthesis:
+
ENZY
Degradation/Digestion:
+
ENZYME
Enzymes are named for the reaction they help:
Sucrose breaks down sucrose
Proteases breakdown proteins
Lipases breakdown lipids
DNA polymerase builds DNA
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Temperature: effects on rates of enzyme activity
Optimum Temperature:
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Greatest number of collisions between enzyme & substrate
For humans its: 35°- 40°C
Raise the Temperature:
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Denature protein
Lower the Temperature:
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Molecules move slower
Fewer collisions between enzyme & substrate
PH: effects on rates of enzyme activity
-The change in PH changes the proteins shapes, so it becomes de
natured.
- Most human enzymes = pH 6-8
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Pepsin (stomach) = pH 3
Trypsin (small intestines) = pH 8