These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Control of glycoprotein synthesis. Kinetic mechanism, substrate specificity, and inhibition characteristics of UDP-N-acetylglucosamine:alpha-D-mannoside beta 1-2 N-acetylglucosaminyltransferase II from rat liver.
    Author: Bendiak B, Schachter H.
    Journal: J Biol Chem; 1987 Apr 25; 262(12):5784-90. PubMed ID: 2952645.
    Abstract:
    Purified rat liver UDP-GlcNAc:alpha-D-mannoside beta 1-2 N-acetylglucosaminyltransferase II (Bendiak, B., and Schachter, H. (1987) J. Biol. Chem. 262, 5775-5783) has been characterized kinetically, and its substrate specificity and inhibition characteristics have been determined. Kinetic data indicate an ordered, or largely ordered sequential mechanism, with UDP-GlcNAc binding prior to the acceptor. The minimal acceptor structure required for full activity is: (Formula: see text) The acceptor molecule must have a terminal Man alpha 1-6 residue, and a terminal GlcNAc beta 1-2Man alpha 1-3 branch to display any activity, but does not require the reducing GlcNAc residue, as the enzyme was about 50% as active after reduction of this residue to N-acetylglucosaminitol. Additional residues (Gal beta 1-4 on the GlcNAc beta 1-2Man alpha 1-3 arm, or a bisecting GlcNAc beta 1-4 on the beta-Man residue) abolish catalytic activity. These results suggest a rigid order in the biosynthesis of all N-linked complex oligosaccharides (bisected and nonbisected bi-, tri-, and tetraantennary), since the enzyme must act to completion prior to the action of either UDP-Gal:GlcNAc beta 1-4 galactosyltransferase or N-acetylglucosaminyltransferase III to make such structures. Inhibition studies with nucleotides, sugars, nucleotide-sugars, and their respective analogues revealed that analogues of UDP and UTP, in which the hydrogen at the 5 position of the uracil was substituted with -CH3, bromine, or mercury (as the mercaptide) were good reversible inhibitors of the enzyme, whereas substitution at other sites lessened the inhibitory potency, usually to a large degree.
    [Abstract] [Full Text] [Related] [New Search]