Inhibition of UDP-GlcNAc:Gal beta 1-3GalNAc-R (GlcNAc to GalNAc) beta 6-N-acetylglucosaminyltransferase from acute myeloid leukaemia cells by photoreactive nitrophenyl substrate derivatives.
Cells from patients with acute myeloid leukaemia (AML) contain an abnormally high UDP-GlcNAc: Gal beta 1-3GalNAc-R (GlcNAc to GalNAc) beta 6-N-acetylglucosaminyltransferase (core 2 beta 6-Gn-T) activity. Upon UV irradiation at 350 nm, the substrate Gal beta 1-3GalNAc alpha-p-nitrophenyl acted as an effective inhibitor for this enzyme but not for several other transferases. Preincubation with Gal beta 1-3GalNAc alpha-benzyl but not GalNAc alpha-benzyl protected core 2 beta 6-Gn-T from inhibition indicating that the inhibitor is specific for the substrate binding site of core 2 beta 6-Gn-T. A number of other nitrophenyl-sugar derivatives similarly acted as inhibitors for core 2 beta 6-Gn-T. GalNAc alpha-pnp at higher concentrations also inactivated UDP-Gal: GalNAc-R beta 3-galactosyltransferase from rat liver and AML cells and inhibition could be reduced by substrate protection. These results suggest that pnp-sugar derivatives may prove useful as specific inhibitors of glycosyltransferases and as affinity labels.
Toki
D
D
Department of Biochemistry, Hospital for Sick Children, Toronto, Ontario, Canada.
Granovsky
M A
MA
Reck
F
F
Kuhns
W
W
Baker
M A
MA
Matta
K L
KL
Brockhausen
I
I
D000116:Acetylgalactosamine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000208:Acute Disease; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000378:metabolism* / Q000494:pharmacology*; D016695:Glycosyltransferases / Q000187:drug effects; D006801:Humans; D007951:Leukemia, Myeloid / Q000201:enzymology*; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000037:antagonists & inhibitors*; D014466:Ultraviolet Rays
D004187:Disaccharides; C085551:beta-D-galactosyl(1-3)-4-nitrophenyl-N-acetyl-alpha-D-galactosamine; D016695:Glycosyltransferases; D017351:N-Acetylglucosaminyltransferases; C053024:beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-acetylglucosaminyl transferase; D000116:Acetylgalactosamine