Transfer of synthetic sialic acid analogues to N- and O-linked glycoprotein glycans using four different mammalian sialyltransferases.
This paper presents kinetic properties of the transfer of several synthetic 9-substituted sialic acid analogues onto N- or O-linked glycoprotein glycans by four purified mammalian sialyltransferases: Gal beta 1,4GlcNac alpha 2,6sialyltransferase, Gal beta-1,4(3)GlcNAc alpha 2,3-sialyltransferase, Gal beta 1,3GalNAc alpha 2,3sialyltransferase, and GalNAc alpha 2,6sialyltransferase. The substituents at C-9 of the sialic acid analogues introduce special biochemical characteristics: 9-Amino-NeuAc represents, up to the present, the first derivative that is resistant toward bacterial, viral, and mammalian sialidases but is transferred by a sialyltransferase. 9-Acetamido-NeuAc, 9-benzamido-NeuAc, and 9-hexanoylamido-NeuAc differ in size and hydrophobic character from each other and from parent NeuAc. 9-Azido-NeuAc may be used to introduce a photoreactive label. The kinetic properties of the four sialyltransferases with regard to the donor CMP-glycosides differed distinctly depending on the structure of the substituent at C-9. CMP-9-amino-NeuAc was only accepted as donor substrate by Gal beta 1,4GlcNAc alpha 2,6sialyltransferase (rat liver), but the Km value was 14-fold higher than that of parent CMP-NeuAc. In contrast, 9-azido-NeuAc was readily transferred by each of these four enzymes. 9-Acetamido-NeuAc, which is a receptor analogue for influenza C virus, 9-benzamido-NeuAc, and 9-hexanoylamido-NeuAc were also accepted by each sialyltransferase, but incorporation values differed significantly depending on the enzyme used. For the first time, the resialylation of asialo-alpha 1-acid glycoprotein with 9-substituted sialic acid analogues by Gal beta 1,4GlcNAc alpha 2,6sialyltransferase is demonstrated.
Gross
H J
HJ
Institut für Biochemie II der Universität Heidelberg, FRG.
Rose
U
U
Krause
J M
JM
Paulson
J C
JC
Schmid
K
K
Feeney
R E
RE
Brossmer
R
R
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005696:Galactosidases / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D011134:Polysaccharides / Q000378:metabolism*; D051381:Rats; D012794:Sialic Acids / Q000378:metabolism*; D012799:Sialyltransferases / Q000378:metabolism*; D013552:Swine; D001616:beta-Galactosidase / Q000378:metabolism*
D006023:Glycoproteins; D011134:Polysaccharides; D012794:Sialic Acids; D012799:Sialyltransferases; D005696:Galactosidases; D001616:beta-Galactosidase