UDP-N-Acteylglucosamine Pyrophosphorylase 1 (UAP1)

The predicted 505-amino acid AgX1 and 521-amino acid AgX2 proteins are globular and cytosolic, and contain motifs indicative of nucleotide binding. Western blot analysis using antibodies against AgX detected approximately 56- and 58-kD proteins in human testis and sperm extracts; only the 58-kD protein was found in placenta, skeletal muscle, and seminal plasma. These masses correlated well with the calculated masses of 55.5 kD and 57.3 kD for AgX1 and AgX2, respectively. Immunofluorescence analysis of human sperm localized AgX to the principal piece of the tail, the neck region of the head, and, to a lesser extent, the midpiece of the tail.In eukaryotes, UDP-GlcNAc is used in the GlcNAc moiety of N-linked glycosylation and the glycosylphosphatidylinositol (GPI)-anchor of cellular proteins.