NagK-8 (N-acetyl-D-glucosmaine Kinase)
N-acetyl-D-glucosamine kinase (NagK) catalyzes the phosphorylation of N-acetyl-D-glucosamine (GlcNAc). ATP is the phosphate donor. The enzyme primarily acts on cytoplasmic GlcNAc derived from cell wall degradation as part of peptidoglycan recycling, or deglycosylated proteins. Wild-type NagK is 303 amino acids in length with a mass of 32.9 kDa. NagK-8 is an engineered 33.9 kDa recombinant protein of 309 residues, which can be used to quantify GlcNAc levels in aqueous samples. One Unit of NagK is defined as the amount of enzyme needed to oxidize 1 μmole of NADH (equivalent to 1 μmole phosphorylate GlcNAc) per min at 30°C.