Open AccessKinetic Parameters of a β‐ d ‐Galactoside α2→6 Sialyltransferase from Embryonic Chicken Liver
Author(s) -
BENDIAK Brad,
COOK Geoffrey M. W.
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb06972.x
Subject(s) - sialyltransferase , galactoside , embryonic stem cell , biology , embryo , andrology , chemistry , biochemistry , microbiology and biotechnology , medicine , enzyme , gene
A β‐ d ‐galactoside α2→6 sialyltransferase was purified 500‐fold in 14% yield from 14‐day embryonic chicken liver. Characterization of the product of the sialyltransferase catalysis was accomplished by separation and permethylation of double‐labelled ([ 14 C]NeuAc, [ 3 H]Gal) oligosaccharides following their release from the glycoprotein fetuin by hydrazinolysis. The enzyme transfers NeuAc to Gal(β1→4)GlcNAc(β1→)R‐terminated oligosaccharides; no activity was found towards Gal(β1→3)GalNAc(α1→)R structures. The trisaccharide, NeuAc(α2→6)Gal(β1→4)Glc, was shown to be a good inhibitor of the sialyltransferase. Kinetic investigations of the enzyme indicate it to have a sequential, random bi‐bi mechanism.