Mode of action of chitin deacetylase from Mucor rouxii on N-acetylchitooligosaccharides

The mode of action of chitin deacetylase from the fungus Mucor rouxii on N- acetylchitooligosaccharides with a degree of polymerization 1-7 has been el ucidated. identification of the sequence of chitin oligomers following enzymatic deac etylation was verified by the alternative use of two specific exo-glycosida ses in conjunction with HPLC. The results were further verified by H-1-NMR spectroscopy. It was observed that the length of the oligomer is important for enzyme act ion. The enzyme cannot effectively deacetylate chitin oligomers with a degr ee of polymerization lower than three. Tetra-N-acetylchitotetraose and pent a-N-acetylchitopentaose an fully deacetylated by the enzyme, while in the c ase of tri-N-acetylchitutriose, hexa-N-acetylchitohexaose and hepta-N-acety lchitoheptaose the reducing-end residue always remains intact. Furthermore, the enzyme initially removes an acetyl group from the nonreducing-end resi due of all chitin oligomers with a degree of polymerization higher than 2, and further catalyses the hydrolysis of the following acetamido groups in a processive fashion. The results are in agreement with the mode of action that the same enzyme e xhibits on partially deacetylated water soluble chitosan polymers.