Bioconversion of chitin to chitosan: purification and characterization of chitin deacetylase from Mucor rouxii.
Chitin deacetylase, the enzyme that catalyzes the hydrolysis of acetamido groups of N-acetylglucosamine in chitin, has been purified to homogeneity from mycelial extracts of the fungus Mucor rouxii and further characterized. The enzyme exhibits a low pI (approximately 3). Its apparent molecular mass was determined to be approximately 75 kDa by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and approximately 80 kDa by size-exclusion chromatography, suggesting that the enzyme exists as a monomer. Carbohydrate analysis of purified chitin deacetylase revealed that the enzyme is a high-mannose glycoprotein and that its carbohydrate content is approximately 30% by weight. Chitin deacetylase is active on several chitinous substrates and chitin derivatives. The enzyme requires at least four N-acetylglucosamine residues (chitotetraose) for catalysis, and it is inhibited by carboxylic acids, particularly acetic acid. When glycol chitin (a water-soluble chitin derivative) was used as substrate, the optimum temperature for enzyme activity was determined to be approximately 50 degrees C and the optimum pH was approximately 4.5.
Kafetzopoulos
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D
Enzyme Technology Division, Institute of Molecular Biology and Biotechnology, Crete, Greece.
Martinou
A
A
Bouriotis
V
V
D000581:Amidohydrolases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D001711:Biotransformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D002686:Chitin / Q000031:analogs & derivatives* / Q000378:metabolism*; D048271:Chitosan; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008969:Molecular Sequence Data; D009089:Mucor / Q000201:enzymology*; D009844:Oligosaccharides / Q000378:metabolism; D013379:Substrate Specificity
D000596:Amino Acids; D002241:Carbohydrates; D009844:Oligosaccharides; D002686:Chitin; D048271:Chitosan; D000581:Amidohydrolases; C019866:chitin deacetylase