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The action of N ‐acetylglucosaminyltransferase‐V is prevented by the bisecting GlcNAc residue at the catalytic step
Author(s) -
Sasai Ken,
Ikeda Yoshitaka,
Eguchi Hironobu,
Tsuda Takeo,
Honke Koichi,
Taniguchi Naoyuki
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)02916-2
Subject(s) - residue (chemistry) , chemistry , acceptor , moiety , stereochemistry , oligosaccharide , enzyme , monosaccharide , catalysis , substrate specificity , biochemistry , condensed matter physics , physics
Using a purified protein and bisected acceptor oligosaccharides, we demonstrate that N ‐acetylglucosaminyltransferase (GnT)‐V transfers a N ‐acetylglucosamine residue via a β1,6‐linkage to the bisected oligosaccharides. We also kinetically characterized the substrate specificity of GnT‐V with respect to the bisected oligosaccharide. Although the K m values for the bisected acceptors were comparable to that for a non‐bisected acceptor, the V max values for the bisected acceptors were much lower than that for the non‐bisected acceptor. These findings suggest that the acceptor specificity of GnT‐V is determined by the catalytic process rather than by its binding to the substrate. It was also found that the presence of the 2‐ N ‐acetyl group in the bisecting monosaccharide moiety plays a critical role in determining the catalytic efficiency of the enzyme.