Hölttä E, Pohjanpelto P
Biochim Biophys Acta. 1982 Dec 30;721(4):321-7. doi: 10.1016/0167-4889(82)90085-4.
We recently isolated a Chinese hamster ovary cell line which grows well without serum but requires the exogenous polyamines putrescine, spermidine or spermine for continuous replication. Here we show that these cells are defective in the arginase-catalyzed synthesis of ornithine, the precursor of polyamines, and that ornithine can replace polyamines in the medium for supporting growth of the cells. The activities of two other key enzymes of polyamine biosynthesis, ornithine decarboxylase and adenosylmethionine decarboxylase, are clearly detectable and show increase during polyamine starvation. In ornithine-and polyamine-free medium cellular putrescine and spermidine are rapidly depleted while the concentration of spermine decreases only moderately. We show further that the cells are able to grow in serum-containing medium without added ornithine or polyamines. This is explained by our finding that serum contains arginase which synthesizes ornithine from arginine in the medium. All the sera from different animal species tested contained arginase activity although in greatly varying amounts. Serum-free medium is therefore essential for expression of arginase deficiency in cells in tissue culture. The eventual importance of polyamines for serum-free cultures in general is discussed.
我们最近分离出一种中国仓鼠卵巢细胞系，该细胞系在无血清条件下生长良好，但需要外源性多胺（腐胺、亚精胺或精胺）才能持续复制。在此我们表明，这些细胞在精氨酸酶催化的多胺前体鸟氨酸的合成过程中存在缺陷，并且鸟氨酸可以替代培养基中的多胺来支持细胞生长。多胺生物合成的另外两种关键酶，鸟氨酸脱羧酶和腺苷甲硫氨酸脱羧酶的活性清晰可测，并且在多胺饥饿期间会增加。在不含鸟氨酸和多胺的培养基中，细胞内的腐胺和亚精胺会迅速耗尽，而精胺的浓度仅适度下降。我们进一步表明，这些细胞能够在添加了血清但未添加鸟氨酸或多胺的培养基中生长。这可以通过我们的发现来解释，即血清中含有精氨酸酶，该酶可在培养基中由精氨酸合成鸟氨酸。尽管不同动物物种的所有血清中精氨酸酶活性差异很大，但均含有该活性。因此，无血清培养基对于在组织培养中细胞精氨酸酶缺陷的表达至关重要。本文还讨论了多胺对于一般无血清培养的最终重要性。
