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Bioconversion of chitin to chitosan: purification and characterization of chitin deacetylase from Mucor rouxii.

1993; National Academy of Sciences; Volume: 90; Issue: 7 Linguagem: Inglês

10.1073/pnas.90.7.2564

1091-6490

Dimitris Kafetzopoulos, Aggeliki Martinou, Vassilis Bouriotis,

Phytase and its Applications

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.