UDP-N-acetylhexosamine pyrophosphorylase (antigen X, AGX, sperm-associated antigen 2, [Includes: UDP-N-acetylgalactosamine pyrophosphorylase (AGX-1); UDP-N-acetylglucosamine pyrophosphorylase (AGX-2)], UAP1 SPAG2)

Function: 1) UDP-GlcNAc biosynthesis from Fru-6-P, 4th (last) step 2) converts UDP & GlcNAc-1-P into UDP-GlcNAc, & UDP & GalNAc-1-P into UDP-GalNAc 3) isoform AGX1 has 2-3X higher activity towards GalNAc-1-P 4) isoform AGX2 has 8X more activity towards GlcNAc-1-P UTP + N-acetyl-alpha-D-glucosamine 1-phosphate diphosphate + UDP-N-acetyl-D-glucosamine Structure: - monomer & homodimer - isoform AGX1 is a homodimer - isoform AGX2 is a monomer Compartment: - cytoplasm - in spermatozoa, localized to the principal piece of the tail, the neck region of the head & to a lesser extent, the midpiece of the tail Alternative splicing: named isoforms=3 Expression: - widely expressed - isoform AGX1 is more abundant in testis than isoform AGX2 - isoform AGX2 is more abundant than isoform AGX1 in somatic tissue - expressed at low level in placenta, muscle & liver Pathology: - antigen implicated in antibody-mediated male infertility

Properties

SIZE: MW = 59 kD entity length = 522 aa COMPARTMENT: cytoplasm MOTIF: binding site SITE: 108-111 FOR-BINDING-OF: Substrate binding site SITE: 223-223 FOR-BINDING-OF: Substrate binding site SITE: 303-304 FOR-BINDING-OF: Substrate binding site SITE: 407-407 FOR-BINDING-OF: Substrate

Database Correlations

OMIM 602862 UniProt Q16222 Pfam PF01704 ENZYME 2.7.7.23

References

UniProt :accession Q16222