Ionomycin, a carboxylic acid ionophore, transports Pb(2+) with high selectivity.
Ionomycin, a carboxylic acid ionophore, transports Pb(2+) with high selectivity.
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Ionomycin 是一种羧酸离子载体，具有高选择性转运 Pb(2 )。
DOI：
10.1074/jbc.275.10.7071
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Pfeiffer,DR
中科院分区：
文献类型：
--
作者：
Erdahl,WL;Chapman,CJ;Taylor,RW;Pfeiffer,DR
Studies utilizing phospholipid vesicle loaded with chelator/indicators for polyvalent cations show that ionomycin transports divalent cations with the selectivity sequence Pb2+> Cd2+> Zn2+> Mn2+> Ca2+> Cu2+> Co2+> Ni2+> Sr2+. The selectivity of this ionophore for Pb2+is in contrast to that observed for A23178 and 4-BrA23187, which transport Pb2+at efficiencies that are intermediate between those of other cations. When the selectivity difference of ionomycin for Pb2+versusCa2+was calculated from relative rates of transport, with either cation present individually and all other conditions held constant, a value of ∼450 was obtained. This rose to ∼3200 when both cations were present and transported simultaneously. 1 μmPb2+inhibited the transport of 1 mmCa2+by ∼50%, whereas the rate of Pb2+transport approached a maximum at a concentration of 10 μmPb2+when 1 mmCa2+was also present. Plots of log rateversuslog ionomycin or log Pb2+concentration indicated that the transporting species is of 1:1 stoichiometry, ionophore to Pb2+, but that complexes containing an additional Pb2+may occur. The species transporting Pb2+may include H·IPb·OH, wherein ionomycin is ionized once and the presence of OH−maintains charge neutrality. Ionomycin retained a high efficiency for Pb2+transport in A20 B lymphoma cells loaded with Indo-1. Both Pb2+entry and efflux were observed. Ionomycin should be considered primarily as an ionophore for Pb2+, rather than Ca2+, of possible value for the investigation and treatment of Pb2+intoxication.
