The ionophore nigericin transports Pb2+ with high activity and selectivity: a comparison to monensin and ionomycin.
The ionophore nigericin transports Pb2+ with high activity and selectivity: a comparison to monensin and ionomycin.
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DOI：
10.1021/bi048175z
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发表时间：
2004-12
期刊：
影响因子：
2.9
通讯作者：
S. Hamidinia;B. Tan;W. Erdahl;C. J. Chapman;Richard W. Taylor;D. Pfeiffer
中科院分区：
文献类型：
--
作者：
S. Hamidinia;B. Tan;W. Erdahl;C. J. Chapman;Richard W. Taylor;D. Pfeiffer
K（+）离子载体尼日利亚菌素作为Pb（2+）的离子载体是非常有效的，但对于其他二价阳离子，包括Cu（2+）、Zn（2+）、Cd（2+）、Mn（2+）、Co（2+）、Ca（2+）、Ni（2+）和Sr（2+），则不是。在该组中，观察到Cu（2+）转运的较小活性，而对于其他活性接近或低于检测限。尼日利亚菌素对Pb（2+）的选择性超过离子霉素或莫能菌素，至少部分是由于尼日利亚菌素-Pb（2+）络合物的高稳定性。对数速率与对数Pb（2+）或对数离子载体浓度的曲线图，以及pH依赖性，表明尼日利亚菌素运输Pb（2+）通过物种NigPbOH和主要是电中性的机制。与莫能菌素和离子霉素一样，一小部分活性可能是产电的，这是基于阻止跨膜电位形成的试剂产生的速率刺激。生理浓度的Ca（2+）或Mg（2+）不抑制尼日利亚菌素催化的Pb（2+）转运，而K（+）和Na（+）浓度在0-100 mM范围内仅对尼日利亚菌素催化的Pb（2+）转运有轻微影响。
The K(+) ionophore nigericin is shown to be highly effective as an ionophore for Pb(2+) but not other divalent cations, including Cu(2+), Zn(2+), Cd(2+), Mn(2+), Co(2+), Ca(2+), Ni(2+), and Sr(2+). Among this group a minor activity for Cu(2+) transport is seen, while for the others activity is near or below the limit of detection. The selectivity of nigericin for Pb(2+) exceeds that of ionomycin or monensin and arises, at least in part, from a high stability of nigericin-Pb(2+) complexes. Plots of log rate vs log Pb(2+) or log ionophore concentration, together with the pH dependency, indicate that nigericin transports Pb(2+) via the species NigPbOH and by a mechanism that is predominately electroneutral. As with monensin and ionomycin, a minor fraction of activity may be electrogenic, based upon a stimulation of rate that is produced by agents which prevent the formation of transmembrane electrical potentials. Nigericin-catalyzed Pb(2+) transport is not inhibited by physiological concentrations of Ca(2+) or Mg(2+) and is only modestly affected by K(+) and Na(+) concentrations in the range of 0-100 mM. These characteristics, together with higher selectivity and efficiency, suggest that nigericin may be more useful than monensin in the treatment of Pb intoxication.