Enzymes are types of proteins
that, in small quantities, increase the rate of biological reactions
without being used-up in the reactions themselves.
That is: Enzymes can act as catalysts.
Enzymes form within living cells
and may act either within the cell or outside it.
Many enzymes are unstable and are easily de-activated, e.g. by heat
or by other chemicals.
Certain enzymes are essential for normal functioning and development
of the human body. Failure in the production or activity of even a single
enzyme can lead to serious problems such as medical disorders.
How do enzymes act as catalysts ?
Enzymes act by binding with the substance involved
in the reaction (called the "sub-strate")
and converting it to another substance (called the "product"
of the reaction).
Particular enzymes catalyse specific reactions.
There are many different enzymes that assist in many of the
huge range of different biochemical reactions. Even when considering
the specific enzyme that could help with a particular reaction, each
enzyme needs certain conditions in order to act as a catalyst
with the maximum possible efficiency - for that particular enzyme facilitating
that particular reaction.
Such conditions may include:
A particular temperature range,
A particular range of pH values,
The presence of specific other enzymes (called "co-enzymes"),
The lack of particular inhibitors (i.e. substances that
reduce or prevent that particular reaction).
Names of specific enzymes:
The names of many enzymes end with the suffix "-ase".
They are generally named according to either the substrate on which
they act (e.g. lactase), or according to the type of reaction they catalyse