Definition of enzyme, characteristics of enzyme, function of enzyme, mechanism action of enzyme, differences between enzyme and catalyst, activity of enzymes, stability of enzymes

2.  To define enzyme
 To describe characteristics of enzyme
 To know the function of enzyme
 To describe mechanism action of enzyme
 To know the differences between enzyme and
catalyst
 To know the activity of enzymes
 To know the stability of enzymes

3.  Enzymes are protein that speed up the rate of
the chemical reaction.
 They are like any catalyst and are not
consumed in chemical reactions, nor do they
alter the equilibrium of a reaction.
 A small quantity of enzyme can bring about the
decomposition of large amount of the
substrate.

4.  Their action is highly specific, i.e. a particular
enzyme can bring about a particular reaction.
 An enzyme is most reactive at a particular
temperature, called optimum temperature.
 Enzymes like other catalysts are influenced by
the presence of other substances, called co-
enzymes acts as promoters.
 They do not take part in the reaction.

5.  They are destroyed by the ultra violet light and
by heat.
 At temperatures to low (0`C) and too high (70-
80`C) the enzymes are most inactive.
 They bring about many complex reactions, e.g.
oxidation, reduction, hydrolysis etc.

6.  The basic function of an enzyme is to increase
the rate of the reaction.
 Enzymes act specifically with only one reactant
(called a substrate) to produce product.
 Enzymes are regulated from a state of low
activity to high activity and vice versa.

7. • Substrate approaches active site.
• Enzyme-substrate complex forms.
• Substrate transformed into product.
• Products released.
• Enzyme recycled.

8.  The area of an enzyme that binds to the
substrate structure has a unique geometric
shape that is designed to fit the molecular
shape of the substrate.
 Each enzyme is substrate specific.
 Thus the active site that is complementary to
the geometric shape of a substrate molecules.

9.  Proposed by EMIL FISCHER in 1894
 The enzyme and the substrate possess specific
complementary geometric shapes that fit
exactly into one another.
 There is no change in active site before and
after a chemical reaction.
 Amino acid groups in the active site help
substrate bind.

10. Catalyst Enzyme
Catalysts are substances that
increase or decrease the rate
of a chemical reaction but
remain unchanged.
Enzymes are proteins that
increase rate of chemical
reactions converting
substrate into product.
Low molecular weight
compounds.
High molecular weight
globular proteins.
There are two types of
catalysts – positive and
negative catalysts
There are two types of
enzymes - activation
enzymes and inhibitory
enzymes.

11. Catalyst Enzyme
Catalysts are simple
inorganic molecules.
Enzymes are complex
proteins.
Inorganic catalyst. Organic catalyst or bio
catalyst.
Reaction rates typically
slower.
Reaction rates several times
faster.

12. Catalyst Enzyme
They are not specific and
therefore end up producing
residues with errors
Enzymes are highly specific
producing large amount of
good residues
C-C and C-H absent C-C and C-H present
Ex: vanadium oxide Ex: amylase, lipase
Similarities
Lowers activation energy. Lowers activation energy.

13.  Enzyme activity is a measure of the quantity of
active enzyme present.
 Enzyme activity = moles of substrate converted
per unit time = rate × reaction volume.
 The SI unit of enzyme activity is the katal.
 1 katal = 1 mol s−1

14.  Enzyme Stabilization is gaining importance
due to the wide range of enzyme applications.
Other than medical research, they can be used
in food, chemical and pharmaceuticals
industries.
 To use these biocatalysts called enzymes to
their full potential, it is very important to
achieve progess in enzyme stabilization.