Pectinase Pectinase
is a general term for enzymes that break down pectin, a polysaccharide substrate
that is found in the cell walls of plants. One of the must studied and widely
used commercial pectinases is polygalacturonase. It is useful because pectin
is the jelly-like matrix which helps cement plant cells together and in which
other cell wall components, such as cellulose fibrils, are embedded. Therefore
pectinase enzymes are commonly used in processes involving the degradation of
plant materials, such as speeding up the extraction of fruit juice from fruit,
including apples. Pectinases have also been used in wine production since
the 1960s.
Like all enzymes, pectinases have an optimum temperature
and pH at which they are most active. For example, a commercial pectinase might
typically be activated at 45 to 55 °C and work well at a pH of 4.8 to 5. If
it is hotter it will make the reaction go more quickly. However, the higher temperature
will eventually denature the enzyme, eventually stopping it from working. Pectinase
also breaks down pectin best at a pH of 4.8 to 5; too high or too low a PH would
also result in the enzyme denaturing. The logical explaination of why the enzyme
denatures would be that if the pH is decreased too much, there would be too many
H+ ions around the protein and thus the H+ ions would be attracted to the places
in the enzyme which were more negative than the enzyme, thus forming a hydrogen
bond there. Also, if the pH is increased, there would be too many OH- ions and
they would interact with the positive regions in the protein. This negative or
positive region could possibly be in the active site, and even if it is not it
does end up disfiguring the enzyme. Due to the fact that the enzyme-substrate
interaction is so specific, even the slightest deformity of the active site directly
or indirectly will result in the enzyme involved not working properly. This change,
if permanent, will render the enzyme useless, denaturing it.Enzyme - stub
Pectinases
are actually a mixture of enzymes, which, along with others such as cellulase,
are widely used in the fruit juice industry where they are widely used to help
extract, clarify and modify fruit juices.
Pectins are large polysaccharide
molecules, made up (mainly) of chains of several hundred galacturonic acid residues.
Enzymes in this pectinase group include polygalacturonases, pectin methyl esterase
and pectin lyases. These Pectinase enzymes act in different ways on the
pectins, which are found in the primary cell walls and in the middle lamella.
Pectins are well known also for their ability to form gels.
Pectinases
are produced during the natural ripening process of some fruits, where together
with cellulases, they help to soften their cell walls. These enzymes are also
secreted by plant pathogens such as the fungus Monilinia fructigena and
the soft-rot bacterium Erwinia carotovora, as part of their strategy for
penetrating the plant host cell walls. In fact, the products of such enzyme assaults
(oligosaccharins) act as a signal which induces uninfected cells to defend themselves.
Pectinases
are found in two main sources-plants and fungi.In plants they are involved in
maturation. In certain fungi they are important for breaching plant cell walls.
The major commercial source of Pectinases is Aspergillus sp.These
fungi produce a complex of enzymes,including endo and ectopectinase, pectiesterase
and pectin lyases. These enzymes are used industrially to weaken cell walls and
enhance extraction of fruit juice. They help to decrease viscosity and prevent
gelation in the extracts. Applications: - Used
in fruit juce industry
- As
a animal feed supplement
- As
a Nutraceutical
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