N-acetylglucosamine (NAG) is the basic building block of many important polysaccharides in living cells, especially in the exoskeleton of crustaceans. It is an important precondition for bifidum synthesis and has many important physiological functions in vivo. For example, it can be used as a chitin monomer, formed by β-1, 4-glycosidic linkage. The chemical formula is C8H15NO6. It is white powder. It has the property of being soluble in water. It has anti-inflammatory, anti-tumor and antioxidant effects, and is a drug for the treatment of osteoarthritis and rheumatoid arthritis in clinical practice. It is widely used in food, medicine, cosmetics and other fields [1], and can be used as a food antioxidant, food additive for infants and children, and sweetener for diabetics. It is mainly used to enhance the function of the human immune system clinically, inhibit the excessive growth of cancer cells or fibrocells, and play a role in the inhibition and treatment of cancer and malignant tumors. For a variety of inflammation, can play an effective treatment, osteoarthritis and joint pain also has a therapeutic effect.

N-acetyl-L-glutamine is an N(2)-acetylglutamine that has L-configuration. It has a role as a human metabolite. It is a N-acetyl-L-amino acid, a N(2)-acyl-L-glutamine and a N(2)-acetylglutamine. It is a conjugate acid of a N-acetyl-L-glutaminate. It is an enantiomer of a N(2)-acetyl-D-glutamine.

N-Acetylglutamine (NAcGln) is a modified amino acid (an acetylated analogue of glutamine) and is a metabolite present in normal human urine. The decomposition products of NAcGln have been identified by NMR and HPLC-MS as N-acetyl-L-glutamic acid, N-(2,6-dioxo-3-piperidinyl) acetamide, pyroglutamic acid, glutamic acid, and glutamine. NAcGln is used for parenteral nutrition as a source of glutamine since glutamine is too unstable whereas NAcGln is very stable. In patients treated with aminoglycosides and/or glycopeptides, an elevation of NAcGln in urine suggests renal tubular injury. High amounts of N-acetylated amino acids (i.e. N-acetylglutamine) were detected in a patient with aminoacylase I deficiency (EC 3.5.1.14, a homodimeric zinc-binding metalloenzyme located in the cytosol), a novel inborn error of metabolism