Everything about Chitin totally explained
Chitin (
C8H13O5N)
n is a long-chain
polymer of a N-acetylglucosamine, a derivative of glucose, and it's found in many places throughout the natural world. It is the main component of the
cell walls of
fungi, the
exoskeletons of
arthropods, such as
crustaceans (like the
crab,
lobster and
shrimp) and the
insects, including
ants,
beetles and
butterflies, the
radula of
mollusks and the beaks of the
cephalopods, including
squid and
octopuses. Chitin has also proven useful for several medical and industrial purposes. Chitin is a biological substance which may be compared to the polysaccharide
cellulose and to the protein
keratin. Although keratin is a protein, and not a carbohydrate, both keratin and chitin have similar structural functions.
Chemistry, physical properties and biological function
Chitin is a
polysaccharide; it's
synthesized from units of
N-acetylglucosamine (more completely, N-acetyl-D-glucos-2-amine). These units form covalent β-1,4 linkages (similar to the linkages between
glucose units forming
cellulose). Chitin may therefore be described as
cellulose with one
hydroxyl group on each
monomer substituted with an
acetylamine group. This allows for increased
hydrogen bonding between adjacent
polymers, giving the chitin-polymer matrix increased strength.
In its unmodified form, chitin is translucent, pliable, resilient and quite tough. In
arthropods, however, it's often modified, becoming embedded in a hardened
proteinaceous matrix, which forms much of the
exoskeleton. In its pure form it's leathery, but when encrusted in
calcium carbonate it becomes much harder. The difference between the unmodified and modified forms can be seen by comparing the body wall of a
caterpillar (unmodified) to a
beetle (modified).
Chitin is one of many naturally occurring
polymers. Its breakdown may be catalyzed by
enzymes called
chitinases, secreted by microorganisms such as
bacteria and
fungi, and produced by some plants. Some of these microorganisms have
receptors to simple
sugars from the decomposition of chitin. If chitin is detected, they then produce enzymes to digest it by cleaving the
glycosidic bonds in order to convert it to simple sugars and
ammonia.
Chemically, chitin is closely related to
chitosan (a more water-soluble derivative of chitin). It is also closely related to
cellulose in that it's a long unbranched chain of
glucose derivatives. Both materials contribute structure and strength, protecting the organism.
Etymology
The English word "chitin" comes from the
French word "chitine", which first appeared in 1836. These words were derived from the
Latin word "chitōn", meaning
mollusk. That is either influenced by, or related to the
Greek word
khitōn, meaning "
tunic" or "
frock", the Central
Semitic word "*kittan", the
Akkadian words "kitû" or "kita’um", meaning
flax or
linen, and the
Sumerian word "gada" or "gida".
A similar word, "
chiton", refers to a marine animal with a protective shell (also known as a "sea cradle").
Uses
Industrial
Chitin is used industrially in many processes. It is used in
water purification, and as an additive to thicken and stabilize foods and pharmaceuticals. It also acts as a binder in dyes, fabrics, and adhesives. Industrial separation membranes and ion-exchange resins can be made from chitin. Processes to size and strengthen paper employ chitin.
Medicine
Chitin's properties as a flexible and
strong material make it favourable as
surgical thread. Its
biodegradibility means it wears away with time as the wound heals. Moreover, chitin has some unusual properties that accelerate healing of wounds in
humans. Chitin has even been used as a stand-alone wound-healing agent. Chitin is used to make
Chitosan, a product with numerous commercial and possible biomedical uses. Its most famous use is as a weight loss product.
Occupations associated with high environmental chitin levels, such as shellfish processors, are prone to high incidences of asthma. Recent studies have suggested that chitin may play a role in a possible pathway in human allergic disease. Specifically, mice treated with chitin develop an allergic response, characterized by a build-up of interleukin-4 expressing innate immune cells. Treatment with a chitinase enzyme abolishes the response.
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Agriculture
Most recent studies point out that chitin is a good inductor for
defense mechanisms in plants. It was recently tested as a
fertilizer that can help plants develop healthy
immune responses, and have a much better yield and life expectancy.
Further Information
Get more info on 'Chitin'.
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