Influence of interferon-gamma and extracellular tryptophan on indoleamine 2,3-dioxygenase activity in T24 cells as determined by a non-radiometric assay.
The indoleamine 2,3-dioxygenase (EC 1.13.11.17) activity in human T24 cells has been investigated in cell extracts by using a non-radioactive assay. It is enhanced in a dose-dependent manner up to 25-fold by interferon-gamma. The maximum reaction velocity is increased rather than the Km, which remains at 4 mumol/l. Induction of activity starts 3 h after stimulation and reaches a plateau at 21-48 h. Decreased stimulation was observed in the presence of high L-tryptophan concentrations.
Werner
E R
ER
Institute for Medical Chemistry and Biochemistry, University of Innsbruck, Austria.
Werner-Felmayer
G
G
Fuchs
D
D
Hausen
A
A
Reibnegger
G
G
Wachter
H
H
D002460:Cell Line; D004306:Dose-Response Relationship, Immunologic; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D007371:Interferon-gamma / Q000494:pharmacology*; D007536:Isomerism; D010105:Oxygenases / Q000096:biosynthesis*; D011994:Recombinant Proteins; D013997:Time Factors; D014364:Tryptophan / Q000494:pharmacology*; D014366:Tryptophan Oxygenase; D001743:Urinary Bladder / Q000201:enzymology
D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D011994:Recombinant Proteins; D007371:Interferon-gamma; D014364:Tryptophan; D010105:Oxygenases; D014366:Tryptophan Oxygenase