N-acetylglucosamine kinase (NAGK) converts endogenous N-acetylglucosamine (GlcNAc), a major component of complex carbohydrates, from lysosomal degradation or nutritional sources into GlcNAc 6-phosphate. NAGK belongs to the group of N-acetylhexosamine kinases and is a prominent salvage enzyme of amino sugar metabolism in mammals. The predicted 344-amino acid NAGK protein contains the 5 sequence motifs necessary for the binding of ATP by sugar kinases. NAGK shares 91.6% amino acid similarity with mouse Nagk, for which enzyme activity is detectable in all mouse tissues examined, with highest enzymatic activity in testis. It is hypothesized that NAGK has a general role in the catabolic pathways of GlcNAc as well as of ManNAc.
GlcNAc kinase; N-acetyl-D-glucosamine kinase; N-acetylglucosamine kinase