McMurry L M, Cullinane J C, Petrucci R E, Levy S B
Antimicrob Agents Chemother. 1981 Sep;20(3):307-13. doi: 10.1128/AAC.20.3.307.
A major portion of tetracycline accumulation by susceptible bacterial cells is energy dependent. Inner membrane vesicles prepared from susceptible Escherichia coli cells concentrated tetracycline 2.5 to 5 times above the external concentration when the electron transport substrate D-lactate or reduced phenazine methosulfate was added. This stimulation was reversed by cyanide, 2,4-dinitrophenol, and carbonyl cyanide m-chlorophenyl hydrazone. These vesicles data showed that proton motive force alone could energize tetracycline uptake. The lactate-dependent uptake had a pH optimum of 6.9 and a magnesium optimum of 1 mM and was not saturable up to 400 microM tetracycline. Although the vesicles were not as active as cells in concentrating tetracycline, they were less active to a similar extent in concentrating tetracycline, they were less active to a similar extent in concentrating proline, the transport of which is known to be solely proton motive force dependent. Therefore, we concluded that the active uptake of tetracycline in susceptible cells was largely, if not solely, energized by proton motive force.
敏感细菌细胞积累四环素的主要部分是能量依赖性的。当加入电子传递底物D-乳酸或还原型吩嗪硫酸甲酯时，从敏感大肠杆菌细胞制备的内膜囊泡将四环素浓缩至外部浓度的2.5至5倍。氰化物、2,4-二硝基苯酚和羰基氰化物间氯苯腙可逆转这种刺激作用。这些囊泡数据表明，仅质子动力就可以为四环素的摄取提供能量。依赖乳酸的摄取的最适pH为6.9，最适镁浓度为1 mM，在高达400 microM四环素时不饱和。尽管囊泡在浓缩四环素方面不如细胞活跃，但它们在浓缩脯氨酸方面的活性也同样降低，已知脯氨酸的运输仅依赖质子动力。因此，我们得出结论，敏感细胞中四环素的主动摄取在很大程度上（如果不是完全）是由质子动力提供能量的。
