[(1->4)-N-acetyl-beta-D-glucosaminyl](n)-N-acetyl-alpha-D-glucosamine
[(1->4)-n-acetyl-beta-d-glucosaminyl](n)-n-acetyl-alpha-d-glucosamine
A chitooligosaccharide having an <em>N</em>-acetyl-α-<small>D</small>-glucosamine residue at the reducing end.