NATURE CURE
Role of
Enzymes in Nutrition
Enzymes are
chemical substances produced in the living organism. They are marvellous
organic
catalysts which
are essential to life as they control all the chemical reactions that take
place in a
living system.
Enzymes are part of all living cells, including those of plants and animals.
The term enzyme,
which literally means in yeast’, was coined following the demonstration of
catalytic
properties of yeast and yeast juices. Although enzymes are produced in the
living cell,
they are not
dependent upon the vital processes of the cell and work outside the cell.
Certain
enzymes of yeast,
for instance, when expressed from the yeast cells are capable of exerting
their usual
effect, that is, the conversion of sugar to alcohol.
A striking feature
of enzymes is that while they enter into chemical reaction, they remain intact
in
the process. They
however, act with maximum efficiency at a certain temperature. Lowering the
temperature below
or raising it above this level slows the reaction. A high degree of heat, that
is
above 60 o C,
permanently destroys their action.
It has been
estimated that there are over 20,000 enzymes in the human body. This estimate
is
based on the
number of bodily processes that seem to require action. However, so far only
about 1,000
enzymes have been identified. But their great role in nutrition and other
living
processes has been
firmly established. They are protein molecules made up of chains of amino
acids. They play a
vital role and work more efficiently than any reagent concocted by chemists.
Thus for instance,
a chemist can separate proteins into their component amino acids by boiling
them at 166 o C
for over 18 hours in a strong solution of hydrochloric acid, but the enzymes of
the small
intestines can do so in less than three hours at body temperature in a neutral
medium.
A feature which
distinguishes enzymes from inorganic catalysts is that they are absolutely
specific in their
actions. This means that a particular enzyme can cause reactions involving only
a particular type
of substance or a group of closely related substances. The substance on which
the enzyme acts is
known as "substrate". The specificity of an enzyme is, however,
related to
the formation of
the enzyme-substrate complex which requires that the appropriate groupings of
both substrate and
enzyme should be in correct relative position. The substrate must fit the
enzyme like a key
fits its lock.
Enzymes which are
used in the cells which make them are called intracellular enzymes.
Enzymes which are
produced in cells which secrete them to other parts of the body are known
as extracellular enzymes. Digestive juices are
an example of the latter type.
