Deacetylation of chitin oligosaccharides of dp 2–4 by chitin deacetylase from Colletotrichum lindemuthianum

Chitin oligosaccharides of degree of polymerization 2–4 were deacetylated by purified chitin deacetylase isolated from Colletotrichum lindemuthianum to give their corresponding breakdown products after purification by liquid chromatography. Data from FABMS analyses suggested that N,N′,N″,N″′-tetraacetylchitotetraose and N,N′,N″-triacetylchitotriose were converted into fully-deacetylated corresponding chitosan oligomers. Conversely, N,N′-diacetylchitobiose [(GlcNAc)2] was deacetylated to give a product which showed an [M + H]+ pseudomolecular ion at m/z 383, suggesting that either of the two acetyl groups were removed. Further data from 1H NMR analyses confirmed that the reaction product was 2-acetamido-4-O-(2-amino-2-deoxy-β-d-glucopyranosyl)-2-deoxy-d-glucose [GlcN-GlcNac]. The enzymatic method has three advantageous characteristics over chemical methods: (i) it does not cause unexpected degradation of the sugar chain, (ii) it is highly reproducible, and (iii) unique compounds such as GlcN-GlcNAc may be produced.