PMID- 10542233
OWN - NLM
STAT- MEDLINE
DCOM- 19991213
LR  - 20210209
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 45
DP  - 1999 Nov 5
TI  - Regulation of a cytosolic and nuclear O-GlcNAc transferase. Role of the
      tetratricopeptide repeats.
PG  - 32015-22
AB  - The O-GlcNAc transferase (OGT) is a unique nuclear and cytosolic
      glycosyltransferase that contains multiple tetratricopeptide repeats. We have
      begun to characterize the mechanisms regulating OGT using a combination of
      deletion analysis and kinetic studies. Here we show that the p110 subunit of the 
      enzyme forms both homo- and heterotrimers that appear to have different binding
      affinities for UDP-GlcNAc. The multimerization domain of OGT lies within the
      tetratricopeptide repeat domain and is not necessary for activity. Kinetic
      analyses of the full-length trimer and the truncated monomer forms of OGT suggest
      that both forms function through a random bi-bi kinetic mechanism. Both the
      monomer and trimer have similar specific activities and similar K(m) values for
      peptide substrates. However, they differ in their binding affinities for
      UDP-GlcNAc, indicating that subunit interactions affect enzyme activity. The
      findings that recombinant OGT has three distinct K(m) values for UDP-GlcNAc and
      that UDP-GlcNAc concentrations modulates the affinity of OGT for peptides suggest
      that OGT is exquisitely regulated by the levels of UDP-GlcNAc within the nucleus 
      and cytoplasm.
FAU - Kreppel, L K
AU  - Kreppel LK
AD  - Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland
      21205, USA.
FAU - Hart, G W
AU  - Hart GW
LA  - eng
GR  - R01 HD13563/HD/NICHD NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 528-04-1 (Uridine Diphosphate N-Acetylglucosamine)
RN  - EC 2.4.1.- (N-Acetylglucosaminyltransferases)
RN  - EC 2.4.1.- (UDP-N-acetylglucosamine-peptide beta-N-acetylglucosaminyltransferase)
SB  - IM
MH  - Animals
MH  - Catalytic Domain
MH  - Cell Nucleus/enzymology
MH  - Cytosol/enzymology
MH  - Kinetics
MH  - N-Acetylglucosaminyltransferases/*metabolism
MH  - Protein Conformation
MH  - Rats
MH  - Spodoptera
MH  - Structure-Activity Relationship
MH  - Uridine Diphosphate N-Acetylglucosamine/metabolism
EDAT- 1999/11/05 00:00
MHDA- 1999/11/05 00:01
CRDT- 1999/11/05 00:00
PHST- 1999/11/05 00:00 [pubmed]
PHST- 1999/11/05 00:01 [medline]
PHST- 1999/11/05 00:00 [entrez]
AID - 10.1074/jbc.274.45.32015 [doi]
AID - S0021-9258(19)51521-6 [pii]
PST - ppublish
SO  - J Biol Chem. 1999 Nov 5;274(45):32015-22. doi: 10.1074/jbc.274.45.32015.