Metabolism of glycine in carrot culture cells

"C n.m.r. spectroscopy has been applied to the investigation of glycine metabolism in tobacco cell cultures (Ashworth & Mettler, 1984) and tobacco protoplasts (Neeman c t ul., 1985). These investigations demonstrated that after prolonged incubation of cells with [2-"C]glycine, the C-2 of glycine was incorporated, in equal proportions. in both the C-2 and C-3 positions of serine; serine was the only 17C-labelled metabolite accumulated. We wished to confirm these observations by using the technique of gas chromatography--mass spectrometry (GC-MS) to analyse extracts of carrot cells incubated for 24 h with ( i ) unlabelled glycine, ( i i ) [I-"C]glycine and (iii) [2-13C]glycine. The cells were extracted and then fractionated by ionexchange chromatography before preparing trimethylsilyl (TMS)-derivatives of each fraction for analysis by G C MS, as described previously (Dunstan et ul., 1984). The mass spectra of glycine-tris-TMS derived from cell