title: Nuclear glycogen synthase--fact or artifact?
abstract: According to Oron et al. [FEBS Lett. (1980) 118, 255-258], nuclear glycogen synthase represents an artifact of preparation in rat liver nuclei. We investigated the nuclei isolated from in vitro growing HD33 ascites cells with exclusively cytoplasmic, and from in vivo growing HD33 Ehrlich-Lettré ascites tumor cells with mainly intranuclear, glycogen deposition. Biochemical and ultracytochemical analyses revealed the complete absence of any contamination of the isolated nuclei by cytoplasmic glycogen particles and associated glycogen synthase activity. The glycogen synthase residing in isolated nuclei of in vivo growing HD33 ascites tumor cells represents a truly nuclear enzyme activity.
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology; D006006:Glycogen Synthase / Q000032:analysis*; D008099:Liver / Q000201:enzymology*; D008112:Liver Glycogen / Q000032:analysis; D008854:Microscopy, Electron; D051381:Rats
chemical_list: D008112:Liver Glycogen; D006006:Glycogen Synthase