Herein we propose a new strategy for utilizing amino sugar resources that involves the enzymatic removal of N-acetyl groups from the amino sugar structures instead of hydrolysis of the sugar chains . We chose chitin deacetylase from a Deuteromycete, Colletotrichum lindemuthianum, as a tool for enzymatic deacetylation of amino sugars. We have purified the enzyme from a culture filtrate to electrophoretic homogeneity (944-fold with a recovery of 4.05%). The optimum temperature of the enzyme was 60t, and the optimum pH was 11.5-12.0 when glycol chitin was used as substrate . The enzyme retained 96% of its activity in the presence of 100 mM sodium acetate . The enzyme was active toward chitin oligomers whose degree of polymerization are more than two, and toward partially N-deacetylated water-soluble chitin. The enzyme could convert (GlcNAc) 36 into fully deacetylated corresponding chitosan oligomers. Conversely, (GlcNAc) 2 was partially deacetylated into 2-acetamido-4-0- (2-amino-2-deoxy-β-D-glucopyranosyl) -2-deoxy-D-glucose [GlcNGlcNAc]. The enzymatic deacetylation method has advantageous characteristics over chemical methods: (1) It never causes unexpected side reactions; (2) It is highly reproducible; (3) Unique compounds such as GlcNGlcNAc can be produced. These basic data on characterization of the enzyme will give us important information for its utilization in glycotechnology.