Kinetic parameters of 3-[(123)I]iodo-L-alpha-methyl tyrosine ([(123)I]IMT) transport in human GOS3 glioma cells.
The radiolabelled amino acid 3-[(123)I]iodo-L-alpha-methyl tyrosine ([(123)I]IMT) is a promising tool for the diagnosis and monitoring of brain tumors using single-photon emission tomography (SPECT). However, little is known about the precise kinetics of [(123)I]IMT uptake in human glioma cells. The kinetic analysis of [(123)I]IMT transport in human GOS3 glioma cells yielded a high-affinity apparent Michaelis constant (K(m) = 20.1 +/- 1.5 microM). The maximum transport velocity (V(max)) amounted to 34.8 +/- 1.9 nmol/mg protein/10 min. Competitive inhibition experiments revealed that [(123)I]IMT transport is mediated principally by the sodium-independent system L.
Riemann
B
B
Department of Nuclear MedicineWestfälische Wilhelms-Universität, Münster, Germany. riemanb@uni-muenster.de
Kopka
K
K
Stögbauer
F
F
Halfter
H
H
Ketteler
S
S
Phan
T Q
TQ
Franzius
C
C
Weckesser
M
M
Ringelstein
E B
EB
Schober
O
O
D001692:Biological Transport; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D008781:Methyltyrosines / Q000138:chemical synthesis / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000493:pharmacokinetics*; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D008781:Methyltyrosines; D019275:Radiopharmaceuticals; C030855:3-iodo-alpha-methyltyrosine