In 1833, a French
chemist Anselme Payen
discovered the first
In 1877, German
first used the term
Enzymes are protein molecules which speed
up all biochemical reactions and metabolic
activities occurring inside a living body.
On the basis of their location there are two
types of enzymes:extracellular and
a set of chemical processes occurring within a living
organism that are necessary for the maintenance of
our bodies get the energy they need from food
Helps in moving, thinking, growing, reproducing
Catabolism is the set of metabolic pathways that
breaks down molecules into smaller units to
• Anabolism is the set of metabolic pathways that
construct molecules from smaller units.
• These reactions require energy
• are powered by catabolism.
Enzymes are "biological catalysts."
They are produced or derived from living
have the ability to increase the rate of chemical
are not changed or destroyed by the chemical
reaction that they accelerate.
Almost all enzymes are globular proteins which
means that they are made up of long linear chains
of amino acids.
They are held together by peptide bonds.
All enzymes also possess an active site.
All enzymes have an active site . It is the small
portion of the enzyme that is directly involved in
It is normally lined with amino acid residues which
recognize the substrate.
After being recognized the substrate is binded to
the active site and the reaction is carried out.
After being used in a reaction , the active site can
be used again.
In enzyme catalyzed reactions, the molecules at
the beginning of the process, called substrates, are
converted into different molecules, called
In biochemistry, an enzyme substrate is the
material upon which an enzyme acts.
In biochemistry, a product is something that is
formed or manufactured by an enzyme from
minimum energy required to start a reaction
This energy could be in the form of heat,
proteins, or other chemicals.
ENZYMES AND ACTIVATION ENERGY
Enzymes greatly decrease the requirement of
activation energy in these ways:
1. orienting substrates correctly
2. straining substrate bonds or by altering their
3. Providing a favorable micro environment
4. Covalently bonding to the substrate
5. by disrupting the charge distribution on the
Enzymes are specific
In other words, the active site of each
enzyme has a particular substrate to which
it binds. The shape of the substrate
determines its ability to bind to the active
site of a particular enzyme
Enzymes cannot bind to substrates whose
shape is not compatible with the active site
ENZYMES PLACE SUBSTRATE
PEPSIN STOMACH PROTIEN PEPTIDES STOMACH
Enzyme production in a cell is controlled
Production of enzymes is increased or
decreased according to its requirements.
can also be enhanced or diminished in
response to changes in the cell's
an additional non-protein working
• Loosely bound organic cofactor
• transfer chemical groups from one cell to
Series of chemical reactions occurring inside
the products of one reaction are
the substrates for subsequent reactions, and
The activity of an Enzyme is affected by
its environmental conditions. Changing
these alter the rate of reaction caused by the
Proposed by Emil Fischer in 1894
Explained specificity of enzymes
both the enzyme and the substrate
possess specific complementary geometric
shapes that fit exactly into one another
it fails to explain the stabilization of the
transition state that enzymes achieve.
•Proposed by Daniel Koshland in1958
•a modification to the lock and key model
•It states that exposure of an enzyme to a substrate
causes the active site of the enzyme to change
shape in order to allow the enzyme and substrate
Foundation of energy
Life force in all living
Help in thinking, moving,
Speed up all biochemical
Without enzymes, life
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