ABSTRACT

N-acetylglucosamine (NAG) is an amino sugar and the minimum unit of con—guration of chitin, a natural polysaccharide present in crustaceans, insects, and fungi. In animals, it is often found in the skin and cartilage in the form of glycosaminoglycans such as hyaluronan and keratan sulfate. In addition, they are universally present as the main component of cell-surface sugar chains, particularly N-glycoproteins, and free NAG is also present in breast milk (Hoff, 1963).