Enzymes are miracles of
Enzymes are large protein molecules, and like other proteins,
they are made up of long chains of amino acids. Enzymes are present
in all living things, where they perform the essential functions
of converting food to energy and new cell material.
Enzymes are bio-catalyst and can be used to speed up chemical
processes or to make reactions take place that otherwise would
not. Enzymes do this by binding to the starting material (substrate),
catalysing the reactions, and then releasing themselves from the
products so that they can react again. Although the enzyme is
not consumed in the reaction, it does lose its activity over time
and so eventually needs to be replenished.
Compared with other ways of controlling chemical reactions enzymes
are more specific, more efficient and work under milder conditions.
When enzymes are used in an industrial process, these characteristics
can often be used to achieve higher purity and better yields while
saving on energy.
Enzymes can be classified by the types of substrates they work
on. Proteases works on proteins, carbohydrases (amylases) work
on carbohydrates, cellulases work on cellulose and lipases work
on lipids. They can also be classified by the types of reactions
they catalyse. Hydrolases split molecules, synthetases join them
and tranferases move groups of atoms from one molecule to another.
Over two thousand different enzymes have been identified, and
several hundreds are available commercially, but so far only 25
are produced on an industrial scale. Some enzymes are still derived
from plants and animals, including papain from papayas and rennet
from calf stomachs. But the last 100 years, and especially since
mid 1960s, microorganisms have become the most important source
of enzymes. Microorganisms can be selected to produce almost any
kind of enzyme in almost any quantity.
What are Enzymes?
History of Enzymes
How are Enzymes made?