4521 Chitin Chitin is one of the main components in the cell walls of fungi, the exoskeletons of insects and other arthropods (such as crustaceans) as well as fish and frogs. It is a polysaccharide that is constructed from units of acetylglucosamine (more completely, N-acetyl-D-glucose-2-amine). These are linked together in beta-1,4 fashion (in a similar manner to the glucose units which form cellulose). In effect, chitin may be described as cellulose with one hydroxyl group on each monomer replaced by an acetylamine group. This allows for increased hydrogen bonding between adjacent polymers, giving the polymer increased strength. Chitin is the second most abundant polysaccharide in the world (after cellulose). Chitinases break down chitin and are a part of the defence mechanism of mammals against chitin-containing parasites in lower life forms. Under certain circumstances, chitin can act as an allergen. Research using murine models has shown that chitin is a size-dependent microbial-associated molecular pattern (MAMP) that can induce an immunological response via pattern recognition receptors. Medium-sized chitin micro-particles (CMPs) have been shown to induce inflammation, while small-sized CMPs reduce inflammation. Additionally, mammalian chitinases may play a key role in mediating the T-helper 2 cell-driven inflammatory response that is commonly associated with asthma. The high prevalence of asthma among people working with chitinous substances, such as crabs and fungi, suggests that chitin might be an allergen playing a significant role in the development of asthma. 1398-61-4 21252321 C28H49N3O16 White powder. No indication of carcinogenicity to humans (not listed by IARC). If chitin is detected they then produce enzymes to digest the chitin by reducing it to simple sugars and ammonia. It is the second most abundant biopolymer on earth, found especially in insects and fungi. 2014-08-29T06:51:34Z 2018-03-21T17:46:24Z Chitin C00461 17029 14-N-ACETYL-BETA-D-GLUCOSAMINYLN1 true [H][C@@]1(O)OC([H])(CO)[C@@]([H])(COC[C@]2([H])OC([H])(CO)[C@@]([H])(COC[C@]3([H])OC([H])(CO)[C@@]([H])(O)[C@]([H])(O)C3([H])N=C(C)O)[C@]([H])(O)C2([H])N=C(C)O)[C@]([H])(O)C1([H])N=C(C)O C28H49N3O16 InChI=1S/C28H49N3O16/c1-11(35)29-21-19(9-44-8-15-17(5-33)47-28(42)23(25(15)39)31-13(3)37)45-16(4-32)14(24(21)38)7-43-10-20-22(30-12(2)36)27(41)26(40)18(6-34)46-20/h14-28,32-34,38-42H,4-10H2,1-3H3,(H,29,35)(H,30,36)(H,31,37)/t14-,15-,16?,17?,18?,19+,20+,21?,22?,23?,24+,25+,26-,27-,28-/m1/s1 InChIKey=DJHJJVWPFGHIPH-OODMECLYSA-N 683.6992 683.311282535 Exogenous Solid HMDB03362 399508 Kurita, Keisuke; Koyama, Yoshiyuki; Nishimura, Shinichiro; Kamiya, Mami. Facile preparation of water-soluble chitin from chitosan. Chemistry Letters (1989), (9), 1597-8.