Catalysis of the reaction: n-m = D-glucosamine + (n-1)-m. This reaction is the hydrolysis of chitosan or chitosan oligosaccharides to remove a D-glucosamine residue from the non-reducing termini; chitosan is a linear polysaccharide composed of randomly distributed beta-(1->4)-linked D-glucosamine and N-acetyl-D-glucosamine units.
chitosan glucosaminohydrolase activity