Topic
Chitin
About: Chitin is a research topic. Over the lifetime, 6590 publications have been published within this topic receiving 253993 citations.
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Dresden University of Technology1, University Hospital Heidelberg2, Tel Aviv University3, Spanish National Research Council4, Federal University of Rio de Janeiro5, Marche Polytechnic University6, University of Montenegro7, National Autonomous University of Mexico8, American Museum of Natural History9, Aix-Marseille University10, Far Eastern Federal University11, Russian Academy of Sciences12, University of Zurich13
TL;DR: It is suggested that chitin sponge scaffolds, apart from the demonstrated biomedical applications, are highly optimized structures for use as filtering systems, templates for biomineralization as well as metallization in order to produce catalysts.
104 citations
TL;DR: An extracellular chitin deacetylase activity has been purified to homogeneity from autolyzed cultures of Aspergillus nidulans, an acidic glycoprotein with a pI of 2.75 and a 28% (wt/wt) carbohydrate content.
Abstract: An extracellular chitin deacetylase activity has been purified to homogeneity from autolyzed cultures of Aspergillus nidulans. This enzyme is an acidic glycoprotein with a pI of 2.75 and a 28% (wt/wt) carbohydrate content. The apparent M r of the enzyme estimated by SDS/PAGE and Superose 12 (f.p.l.c.) was around 27,000. The enzyme had an optimum pH at 7.0 and was stable in the pH range 4.0–7.5. Its optimum temperature of reaction was 50°C, and it was stable from 30° to 100°C after 1 h of preincubation. The enzyme hydrolyzed glycol chitin and oligomers of N-acetylgucosamine and to a lesser extent chitin, colloidal chitin, carboxymethylchitin, and an α-1 → 3,1 → 6-N-acetylgalactosamine-galactan among other substances with amido groups, but the enzyme did not hydrolyze peptide bonds. The role of this enzyme could be deacetylation of chitin oligosaccharides during autolysis, after action of endochitinase on cell walls.
104 citations
01 Feb 1995
TL;DR: Chitosan is a polyaminosaccharide, normally obtained by alkaline deacetylation of chitin which is a very abundant naturally occurring polymeric material as discussed by the authors.
Abstract: Chitosan [(1-4) 2-amino 2-deoxy-β-D-glucan] is a polyaminosacchar-ide, normally obtained by alkaline deacetylation of chitin which is a very abundant naturally occurring polymeric material. It occurs as a principle constituent of the protective cuticles of crustacea and insects and also in the cell walls of some fungi and microorganisms.
104 citations
TL;DR: Chitin (β (1°4)-N-acetyl-D-glucosamine) and chitosan (deacetylated chitin) are currently available in large quantities as waste products and by-products of the shellfish industry and their potential as carriers for food additives was studied.
Abstract: Chitin (β (1°4)-N-acetyl-D-glucosamine) and chitosan (deacetylated chitin) are currently available in large quantities as waste products and by-products of the shellfish industry. Their potential as carriers for food additives was studied. Significant correlations were found between dye concentration ranging from 0.2–1.6 mg dye (FD&C Red No. 40) per g chitin or chitosan and dye-binding capacity of chitin or chitosan. Within a pH range of 2.0–7.0, dye-binding capacity of chitin was stable. Chitosan gelled below a pH of 5.5 and could not be evaluated but its dye-binding capacity was constant between pH 7.0 and 5.5. Above pH 7.0 dye-binding capacity decreased for chitin as well as for chitosan but between pH 2.0 and 6.0 no dye was released from dyed chitin containing 0.77 mg dye/g chitin.
104 citations
TL;DR: P pH‐activity profiles showed that yeast and hyphae contain a protease‐dependent activity that has an optimum at pH 6.8 and there is an activity that is not activated by proteolysis in vitro and which shows a peak at pH 8.0, suggesting there are two distinct chitin syntheses in C albicans.
Abstract: Chitin synthase activity was studied in yeast and hyphal forms of Candida albicans. pH-activity profiles showed that yeast and hyphae contain a protease-dependent activity that has an optimum at pH 6.8. In addition, there is an activity that is not activated by proteolysis in vitro and which shows a peak at pH 8.0. This suggests there are two distinct chitin synthases in C. albicans. A gene for chitin synthase from C. albicans (CHS1) was cloned by heterologous expression in a Saccharomyces cerevisiae chs1 mutant. Proof that the cloned chitin synthase is a C. albicans membrane-bound zymogen capable of chitin biosynthesis in vitro was based on several criteria. (i) the CHS1 gene complemented the S. cerevisiae chs1 mutation and encoded enzymatic activity which was stimulated by partial proteolysis; (ii) the enzyme catalyses incorporation of [14C]-GlcNAc from the substrate, UDP[U-14C]-GlcNAc, into alkali-insoluble chitin; (iii) Southern analysis showed hybridization of a C. albicans CHS1 probe only with C. albicans DNA and not with S. cerevisiae DNA; (iv) pH profiles of the cloned enzyme showed an optimum at pH 6.8. This overlaps with the pH-activity profiles for chitin synthase measured in yeast and hyphal forms of C. albicans. Thus, CHS1 encodes only part of the chitin synthase activity in C. albicans. A gene for a second chitin synthase in C. albicans with a pH optimum at 8.0 is proposed. DNA sequencing revealed an open reading frame of 2328 nucleotides which predicts a polypeptide of Mr 88,281 with 776 amino acids. The alignment of derived amino acid sequences revealed that the CHS1 gene from C. albicans (canCHS1) is homologous (37% amino acid identity) to the CHS1 gene from S. cerevisiae (sacCHS1).
104 citations