title: A pathway of chitosan formation in Mucor rouxii. Enzymatic deacetylation of chitin.
abstract: 1. An enzyme that catalyzes hydrolysis of acetamido groups of chitin derivatives was found in the supernatant fraction of Mucor rouxii. 2. Partially O-hydroxyethylated chitin (glycol chitin) was used as a substrate in the purification and characterization of this enzyme. A 140-fold purification was obtained by means of ammonium sulfate fractionation followed by chromatography on carboxymethylcellulose and DEAE-cellulose. 3. The enzyme releases about 30% of the acetyl groups of glycol chitin, giving a product with a decreased sensitivity to lysozyme. The enzyme also deacetylates chitin and N-acetylchitooligoses, whereas it is inactive toward bacterial cell wall peptidoglycan, N-acetylated heparin, a polymer of N-acetylgalactosamine, di-N-acetylchitobiose and monomeric N-acetylglucosamine derivatives. 4. This enzyme shows a pH optimum of 5.5. The Km value for glycol chitin is 0.87 g/l or 2.6 mM with respect to monosaccharide residues. 5. The occurrence of this enzyme accounts for the formation of chitosan in fungi.
mesh_terms: D000581:Amidohydrolases / Q000302:isolation & purification / Q000378:metabolism*; D002264:Carboxylic Acids / Q000494:pharmacology; D002413:Cations, Divalent; D002686:Chitin / Q000378:metabolism*; D003101:Collodion; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009089:Mucor / Q000201:enzymology*; D009844:Oligosaccharides / Q000378:metabolism; D013045:Species Specificity
chemical_list: D002264:Carboxylic Acids; D002413:Cations, Divalent; D009844:Oligosaccharides; D002686:Chitin; D003101:Collodion; D000581:Amidohydrolases