Sialyltransferase-1 in a human malignant glioma cell line. Kinetic characteristics and effect of human interferon-beta.
Sialyltransferase-1 activity was studied in cultured 12-18 human glioma cells. The apparent Km and Vmax with variable LacCer concentrations were 32 microM and 197 pmoles/mg protein/hr and with variable CMP-NeuAc concentrations were 172 microM and 877 pmoles/mg protein/hr., respectively. The pH optimum towards exogenous LacCer was 6.0 and towards endogenous acceptors was 6.2. The optimum protein:detergent ratio was 1:1. Human beta interferon (1000 units/ml medium) increased sialyltransferase-1 activity only slightly on a protein basis but increased it 47% on a per cell basis. These results demonstrate that one of the biochemical effects of beta-interferon on 12-18 human glioma cells is to stimulate ganglioside synthesis.
Yates
A J
AJ
Department of Pathology, College of Medicine, Ohio State University, Columbus 43210.
Collins
J F
JF
Elder
P J
PJ
Stephens
R E
RE
D002460:Cell Line; D005909:Glioblastoma / Q000201:enzymology*; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D007700:Kinetics; D011994:Recombinant Proteins / Q000494:pharmacology*; D012799:Sialyltransferases / Q000378:metabolism*
D007370:Interferon Type I; D011994:Recombinant Proteins; D012799:Sialyltransferases