title: Variation of glycinamide ribonucleotide synthetase levels during in vitro aging of human fibroblasts: implications for gene dosage studies.
abstract: The levels of glycinamide ribonucleotide synthetase were monitored in four human fibroblast cell lines, two diploid, one monosomy 21 and one trisomy 21, from early passage number to senescence. In all four lines, enzyme activity increased as the cells aged. Enzyme levels for the diploid versus trisomy 21 cells did not consistently exhibit the expected gene dosage effect.
mesh_terms: D000375:Aging; D019731:Carbon-Nitrogen Ligases; D002460:Cell Line; D004171:Diploidy; D005347:Fibroblasts / Q000201:enzymology* / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D014314:Trisomy
chemical_list: D008025:Ligases; D019731:Carbon-Nitrogen Ligases; C022387:phosphoribosylamine-glycine ligase