Carbohydrate polymers Chitin

Finally, the diversity of the bulk properties of proteins is unequaled in any other known polymer class. Proteins form materials as diverse as the hard substance of nails and hair, the transparent substance of the lens, the elastic substance of collagen, and so on. Some of tliese properties are equaled by polymers in other classes keratin by the carbohydrate polymer chitin (A-acyl-o-glucosamine), the transparency of the lens proteins by the polymer Perspex (polymethyl methacrylate), the toughness and elasticity of collagen by the polyamide nylon. But no single polymer class has demonstrated such a variety of diverse bulk properties. The compaction of so many diverse bulk properties into one polymer class, polypeptides composed of the twenty proteinaceous amino acids, obviously contributes greatly to their biological fitness. 

In the present work, we extend the method to compensate for the hydrogen bonds present in carbohydrates. The hydroxylated character of carbohydrate polymers influences between-chain interactions through networks of hydrogen bonds that occur during crystallization. Frequently, several possible attractive interactions exist that lead to different packing arrangements, and several allomorphic crystalline forms have been observed for polysaccharides such as cellulose, chitin, mannan and amylose. The situation is even more complex when water or other guest molecules are present in the crystalline domains. Another complication is that polysaccharide polymorphism includes different helix shapes as well. 

Kato, Y., Kaminaga, J., Matsuo, R., and Isogai, A., TEMPO-mediated oxidation of chitin, regenerated chitin and N-acetylated chitosan. Carbohydrate Polymers 2004, 58 (4), 421-426. 

Hirano, S., Zhang, M., Chung, B.G., and Kim, S.K. 2000. The A-acylation of chitosan fibre and the A-deacetylation of chitin fibre and chitin-cellulose blended fibre at a solid state. Carbohydr. Polymers 41, 175-179. 

Amyloglucosidase and Sanzyme were obtained from Novo-Nordisk Bio-medical Group, Bangalore and Uni-Sankyo Limited, Hyderabad respectively. Locally available cornstarch was used as a source of carbohydrate polymer. Powdered chitin from crab shels was purchased from Sigma Chemical Company, U.S.A. Reducing values were determined by 3,5-dinitro salicylic acid method [6]. Protein content in Amyloglucosidase was estimated by Folin-phenol method [7]. 

In disaccharides and polymeric carbohydrates, the ether-type radicals such as 7 and 8 have the radical site proximate to the glycosidic linkage and therefore play a major role in its scission (see below). In glucosamine [20] and N-acetylglucosamine [21] as well as in their related polymers chitin, chitosan and hyaluronic acid, one must further consider radicals of the type 9-11. Thus, one may expect that in addition to the behaviour shown by the prototypical carbohydrate radicals, reactions such as are observed with amino acids (c/. [22]) and peptides (c/. [23-25]), may also play a role. 

From among the natural carbohydrate polymers, we mention here cellulose, chitin and its deacetylated form chitosan, hyaluronic acid (hyaluronan), and heparin. Apart from cellulose, the monomer-unit sequences are not strictly regular, but the structures given below are representative. Chitosan, hyaluronic acid, and heparin are water-soluble because they carry electrically-charged functions. Since cellulose and chitin are insoluble in water, most of their radiation chemistry has been done in the solid state, as discussed below. Yields of molecular-weight reduction have usually been determined by viscosimetry and, more recently, by the laser light-scattering technique. 

The most common biopolymers derived from animals are chitin and chito-san. Chitin is a macromolecule found in the shells of crabs, lobsters, shrimps, and insects. The primary unit in the chitin polymer is 2-deoxy-2-(acetylamino) glucose. Chitin can be degraded by chitinase. Chitosan is a modified natural carbohydrate polymer derived from deactylation of chitin, which occurs principally in animals of the phylum Arthropoda. Chitosan is also prepared from squid pens. Chitin is insoluble in its native form but chitosan, the partly deacetylated form, is water soluble. The materials are biocompatible and have antimicrobial activities as well as the ability to absorb heavy metal ions [16]. 

Minagawa T, Okamura Y et al (2007) Effects of molecular weight and deacetylation degree of chitin/chitosan on wound healing. Carbohydr Polym 67 640-644... 

Muzzarelli RAA (1993) Biochemical significance of exogenous chitins and chitosans in animals and patients. Carbohydr Polym 20 7-16... 

Muzzarelli RAA (2009) Chitins and chitosans for the repair of wounded skin, nerve, cartilage and bone. Carbohydr Polym 76 167-182... 

Kurita K et al (2000) Enzymatic degradation of P-chitin susceptibility and the influence of deacetylation. Carbohydr Polym 42(1) 19-21... 

The A. coerulea material was poorly crystalline, showing a broad peak at 20° 20, but the spectrum for the alkali-treated material showed a broad peak at 10.72° and two peaks at 18.72° and 19.98° 20, with close similarity to the spectrum of authentic chitosan. Optical microscopy showed that the alkali-treated products, stained with Saphranine or with other stains, preserved the morphology of the fungus, with flattened and empty structures [30] (Fig. 1). This work introduced the concept that an extended surface area of the carbohydrate polymer leads to enhanced performance, as amply confirmed by most recent works dealing with chitin and chitosan nanofibrils. In fact, the partially re-acetylated chitosan (degree of acetylation 0.23) is promptly depolymerized by lysozyme, papain, and lipase thanks to the ideal degree of acetylation for maximum enzymatic activity. Remarkably, the re-acetylated... 

Ifuku, S., Tsukiyama, Y., Yukawa, T., Egusa, M., Kaminaka, H., Izawa, H., Morimoto, M., Saimoto, H., 2015. Facile preparation of silver nanoparticles immohilized on chitin nanofiber surfaces to endow antifungal activities. Carbohydrate Polymers 117, 813—817. 

Jayakumar, R. Menon, D. Manzoor, K. Nair, S.V. Tamura, H. Biomedical applications of chitin and chitosan based nanomaterials—A short review. Carbohydr. Polym. 2010, 82 (2), 227-232. 

Hagiwara, K., Kuriba3rashi, Y, Iwai, H., Azuma, 1., Tokura, S., Ikuta, K., and Ishihara, C. (1999). A sulfated chitin inhibits hemagglutination by Theileria sergenti merozoites, Carbohydr. Polym., 39, 245-248. 

M.R. Kasaai, Determination of the degree of N-acetylation for chitin and chitosan by various NMR spectroscopy techniques a review, Carbohydr. Polym. 79 (2010) 801-810. 

Ahmed Jalal, U., Masahiro, F., Shinichiro, S., Yasuo, G. Outstanding reinforcing effect of highly oriented chitin whiskers in PVA nanocomposites. Carbohydr. Polym. 87, 799-805 (2012)... 

Sriupayo, J., Supaphol, P., Blackwell, J., Rujiravanit, R. Preparation and characterization of a-chitin whisker-reinforced chitosan nanocomposite films with ot without heat treatment. Carbohydr. Polym. 62, 130-136 (2005a)... 

Fan, Y.M., Saito, T., Isogai, A. Individual chitin nano-whiskers prepared from partially deacetylated -chitin by fibril surface cationization. Carbohydr. Polym. 79, 1046-1051 (2010)... 

Focher, B., Beltrane, P.L., Naggi, A., Torri, G. Alkaline N-deacetylation of chitin enhanced by flash treatments Reaction kinetics and structure modifications. Carbohydr. Polym. 12, 405 18 (1990)... 

Zia, KM., Barikani, M., Zuber, M., Bhatti, I.A., Sheikh, M.A. Molecular engineering of chitin based polyurethane elastomers. Carbohydr. Polym. 74, 149-158 (2008a)... 

Zia, K.M., Barikani, M., Khalid, A.M., Honarkar, H. Surface characteristics of polyurethane elastomers based on chitin/l,4-butanediol blends. Ehsan-ulHaq. Carbohydr. Polym. 77, 621-627 (2009d)... 

Yen, M., Yang, J., Mau, J. Physicochemical characterization of chitin and chitosan from crab shells Carbohydr. Polym. 75, 15-21 (2009)... 

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