Enzymatic transfer of galactosyl phosphate from UDP-galactose to UDP-N-acetylglucosamine

Abstract

The microsomal fraction of hen oviduct homogenate has been shown to contain an enzyme capable of catalyzing a transfer of galactosyl phosphate from UDP-galactose to UDP-N-acetylglucosamine. The product was isolated and identified as UDP-N-acetylglucosamine-6-phosphogalactose, the same compound as that found as a normal constituent in hen oviduct. The enzyme is analogous in reaction type to UDP-N-acetylglucosamine: glycoprotein N-acetylglucosamine-1-phosphotransferase (the enzyme responsible for introducing the recognition marker of newly synthesized lysosomal enzymes), which suggests that the galactosyl phosphotransferase is involved in galactose 1-phosphate transfer to N-acetylglucosamine residues of newly synthesized glycoproteins.