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 (almost-equal-to 3). Its apparent molecular mass was determined to be almost-equal-to 75 kDa by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and almost-equal-to 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 almost-equal-to 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 almost-equal-to 50-degrees-C and the optimum pH was almost-equal-to 4.5.