Identification of N-acetylglucosamine-alpha-1-phosphate transferase activity in Dictyostelium discoideum: an enzyme that initiates phosphoglycosylation.
A lysosomal proteinase from Dictyostelium discoideum was previously shown to have GlcNAc alpha-1-P residues in phosphodiester linkage to serine. We have identified a GlcNAc-alpha-1-P transferase activity in membrane preparations using UDP[3H]GlcNAc and a peptide acceptor with three tandem Ser-Gly repeats. We established an assay, proved the structure of the product, determined the Kms for donor and acceptor and showed that the glycopeptide binds a GlcNAc-alpha-1-P specific rabbit antibody. These findings provide the tools to search for mutants lacking GlcNAc-alpha-1-P transferase activity as a probe for the function of this modification we call phosphoglycosylation.
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La Jolla Cancer Research Foundation, California 92037.
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D000117:Acetylglucosamine / Q000031:analogs & derivatives / Q000032:analysis; D000818:Animals; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D004023:Dictyostelium / Q000201:enzymology*; D006031:Glycosylation; D007074:Immunoglobulin G; D008247:Lysosomes / Q000201:enzymology; D011817:Rabbits / Q000276:immunology; D017855:Transferases (Other Substituted Phosphate Groups) / Q000378:metabolism*
D007074:Immunoglobulin G; C026146:N-acetylglucosamine-1-phosphate; D017855:Transferases (Other Substituted Phosphate Groups); C030012:UDP-N-acetylglucosamine-lysosomal-enzyme-N-acetylglucosaminephosphotransferase; D000117:Acetylglucosamine