Stieger B, Stange G, Biber J, Murer H
J Membr Biol. 1983;73(1):25-37. doi: 10.1007/BF01870338.
Brush border membranes were isolated from rat renal cortex by a divalent cation precipitation method. L-35S-cysteine uptake into the vesicles was measured by a rapid filtration method. Only minimal binding of the amino acid to the vesicles was observed. Sodium stimulates L-cysteine uptake specifically. Anion replacement experiments, experiments in the presence of potassium/valinomycin-induced diffusion potential as well as experiments with a potential-sensitive fluorescent dye document an electrogenic sodium-dependent uptake mechanism for L-cysteine. Tracer replacement experiments as well as the fluorescence experiments indicate a preferential transport of L-cysteine. Transport of L-cysteine is inhibited by L-alanine and L-phenylalanine but not by L-glutamic acid and the L-basic amino acids. Initial, linear influx kinetics provide evidence for the existence of two transport sites. The results suggest (a) sodium-dependent mechanism(s) for L-cysteine shared by other neutral amino acids.
采用二价阳离子沉淀法从大鼠肾皮质分离刷状缘膜。通过快速过滤法测定囊泡对L-35S-半胱氨酸的摄取。仅观察到氨基酸与囊泡的极少结合。钠特异性刺激L-半胱氨酸的摄取。阴离子置换实验、在钾/缬氨霉素诱导的扩散电位存在下的实验以及使用电位敏感荧光染料的实验证明了L-半胱氨酸的电生性钠依赖性摄取机制。示踪剂置换实验以及荧光实验表明L-半胱氨酸的优先转运。L-半胱氨酸的转运受到L-丙氨酸和L-苯丙氨酸的抑制，但不受L-谷氨酸和L-碱性氨基酸的抑制。初始的线性流入动力学为两个转运位点的存在提供了证据。结果表明（a）其他中性氨基酸共享的L-半胱氨酸的钠依赖性机制。
