Glutamine-stimulated modification and degradation of glutamine synthetase in hepatoma tissue culture cells

✍ Scribed by Arad, Gila; Freikopf, Aliza; Kulka, Richard G.

• Book ID: 121940690
• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 970 KB
• Volume: 8
• Category: Article
• ISSN: 0092-8674
• DOI: 10.1016/0092-8674(76)90190-2

✦ Synopsis

Effects of glutamine on glutamine synthetase (GS) activity of hepatoma tissue culture (HTC) cells were studied with the aid of a specific goat anti-rat GS serum. lmmunodiffusion and immunoelectrophoretic tests show that rat liver GS and HTC cell GS are immunologically similar but not identical. lmmunotitrations of HTC cell extracts demonstrate that in cells incubated in high concentrations (5 mM) of glutamine, a cross-reacting form of GS with a decreased enzyme-specific activity accumulates. On prolonged incubation of cells in high glutamine, there is net degradation of GS to form immunologically inactive products. Radioimmunoprecipitation experiments show that glutamine acts by accelerating the degradation of preformed GS.