Damper P D, Epstein W, Rosen B P, Sorensen E N
Biochemistry. 1979 Sep 18;18(19):4165-9. doi: 10.1021/bi00586a018.
The accumulation of 204T1+ by Escherichia coli occurs primarily via either of two K+ transport systems called Kdp and TrkA. T1+ influx is inhibited and T1+ efflux is stimulated by the addition of K+ to the assay medium. Mutants defective in both the Kdp and TrkA systems accumulate little T1+. Uptake of triphenylmethylphosphonium, a lipid-soluble cation whose distribution is widely used to estimate the membrane electrical potential in bacteria, occurs to about the same extent in mutants that accumulate little T1+ as in strains that accumulate T1+ to high levels. These findings indicate that T1+ may be useful as a probe of bacterial K+ transport systems but is not a reliable indicator of the membrane electrical potential in E. coli.
大肠杆菌对204T1+的积累主要通过两种钾离子转运系统中的任意一种，即Kdp和TrkA。向测定培养基中添加钾离子会抑制T1+内流并刺激T1+外流。在Kdp和TrkA系统均有缺陷的突变体积累的T1+很少。三苯甲基鏻是一种脂溶性阳离子，其分布广泛用于估计细菌中的膜电势，在积累少量T1+的突变体中的摄取程度与在积累高水平T1+的菌株中的摄取程度大致相同。这些发现表明，T1+可能用作细菌钾离子转运系统的探针，但不是大肠杆菌膜电势的可靠指标。
