AMINO ACID METABOLISM OF DIFFERENT MAMMALIAN CELL LINES

Abstract

After long-term storage under liquid nitrogen, 16 different mammalian cell lines from normal and malignant origins were cultured in the presence of14C-glucose for 3 and 7 days without a change in growth medium.All cell lines synthesized from glucose at least six amino acids: aspartate, glutamate, serine, alanine, glycine, and threonine. In addition, HeLa S, human heart (HH), and L-929 synthesized cystine after 7 days of incubation without change of growth medium. The most highly labeled compounds were alanine, glycine, and glutamic acid in all cell media. The incorporation of14C into aspartic acid, serine, and threonine was for the most part detected in small amounts.Citrulline appeared in large quantities in the growth medium of HeLa F, HeLa Q, and HeLa Clone S-3, whereas arginine was greatly reduced after the 3-day growth period. At the same time, the ammonia content greatly increased in all three cases. Proline disappeared in the medium of HeLa S, HEp II, human amnion (HA-FL), canine kidney (MD-CK), human appendix (HA-A1), human liver (HL-CW), and human embryonic adrenal (W-AD62). Glutamic acid increased in the medium of monkey kidney (MK-MS) and canine kidney (MD-CK). In the HeLa Clone S-3 medium, lysine decreased and histidine increased.Each cell line in this investigation may be distinguished on the basis of the degree of14C incorporation into glutamic acid, serine, glycine, and alanine, except three pairs of cell lines: HEp II and HA-A1, MD-CK and MK-MS, and rat embryo and HeLa F.