Law S S, Mukkada A J
J Protozool. 1979 May;26(2):295-301. doi: 10.1111/j.1550-7408.1979.tb02784.x.
Leishmania tropica promastigotes transport L-proline through an active uptake system that has saturation kinetics, temperature dependence, a requirement for metabolic energy and transport against a concentration gradient. In experiments lasting 10 min, less than 10% of the proline transported is incorporated into macromolecules. The remainder is largely unaltered proline with an intracellular concentration nearly 60 times that in the reaction mixture. The uptake system has a relatively broad specificty; it is competitively inhibited by D-proline as well as by alanine, methionine, valine, azetidine-2-carboxylate, thioproline, 3,4-dehydropoline, hydroxyproline and alpha-aminoisobutyric acid. Pre-established intracellular proline pools exchange with external proline as well as compounds that compete with it for uptake. Evidence is presented that feedback inhibition and transinhibition may regulate proline uptake in this organism.
热带利什曼原虫前鞭毛体通过一个具有饱和动力学、温度依赖性、需要代谢能量且能逆浓度梯度转运的主动摄取系统来转运L-脯氨酸。在持续10分钟的实验中，所转运的脯氨酸中不到10%被整合到大分子中。其余大部分是未改变的脯氨酸，其细胞内浓度几乎是反应混合物中浓度的60倍。摄取系统具有相对广泛的特异性；它受到D-脯氨酸以及丙氨酸、甲硫氨酸、缬氨酸、氮杂环丁烷-2-羧酸、硫代脯氨酸、3,4-脱氢脯氨酸、羟脯氨酸和α-氨基异丁酸的竞争性抑制。预先建立的细胞内脯氨酸池与外部脯氨酸以及与之竞争摄取的化合物进行交换。有证据表明反馈抑制和反抑制可能调节该生物体中脯氨酸的摄取。
