Bogdanova N P, Nikol'skiĭ N N, Teslenko L V
Tsitologiia. 1983 Jan;25(1):102-6.
The dependence of L-alanine uptake by 3T6 and CHO-K1 cells on Na+ electrochemical gradient has been studied. The Na+ chemical gradient was changed by a short-term (partial or complete) replacement of Na+ for choline. The membrane potential change was achieved by addition of potassium ionophore--valinomycin (10 microM) into the medium. It is determined that the value of Km for alanine uptake by 3T6 cells increases from 2 mM, with 140 mM Na+ in the medium, up to 30 mM, if the replacement of Na+ for choline is complete. Similar results are obtained for CHO cells. The membrane potential increase under the influence of valinomycin leads to the increase in the value of Vmax of the uptake. The data obtained are interpreted on the basis of the well known scheme of Na+ alanine complex transfer, where Na+ increases the affinity of the carrier to the amino acid, and the membrane potential increases the carrier mobility.
研究了3T6和CHO - K1细胞对L - 丙氨酸的摄取对Na⁺电化学梯度的依赖性。通过短期（部分或完全）用胆碱替代Na⁺来改变Na⁺化学梯度。通过向培养基中添加钾离子载体缬氨霉素（10 μM）来实现膜电位变化。已确定，如果完全用胆碱替代Na⁺，3T6细胞摄取丙氨酸的Km值从培养基中含有140 mM Na⁺时的2 mM增加到30 mM。CHO细胞也得到了类似结果。缬氨霉素作用下膜电位的增加导致摄取的Vmax值增加。根据众所周知的Na⁺ - 丙氨酸复合物转运模式对所得数据进行了解释，其中Na⁺增加了载体对氨基酸的亲和力，而膜电位增加了载体的迁移率。
