Coyle P, Zalewski P D, Philcox J C, Forbes I J, Ward A D, Lincoln S F, Mahadevan I, Rofe A M
Division of Clinical Biochemistry, Institute of Medical and Veterinary Science, Adelaide, Australia.
Biochem J. 1994 Nov 1;303 ( Pt 3)(Pt 3):781-6. doi: 10.1042/bj3030781.
Zinquin [ethyl (2-methyl-8-p-toluenesulphonamido-6-quinolyloxy)acetate], a new intracellular zinc fluorophore, was used to reveal and to measure Zn in cultured rat hepatocytes before and after metallothionein (MT) induction. Hepatocytes labelled with an intense extranuclear fluorescence. Culture with combinations of Zn, dexamethasone and interleukin-6, increased intracellular MT by 24-fold, Zn 3-fold, and Zinquin fluorescence by approx. 2-fold above control values. Zinquin fluorescence correlated in descending order with the total cellular Zn (r = 0.747), exchangeable Zn (r = 0.735), soluble cytosolic Zn (r = 0.669) and MT (r = 0.666). When Zinquin was incubated with a cytosolic fraction of liver proteins before Sephadex G-75 column chromatography, it fluoresced with free, MT-incorporated and protein-bound Zn. Although only a slight attenuation of fluorescence was seen with high-molecular-mass protein-bound Zn, MT was degraded by 60% in the presence of Zinquin. The undegraded Zn-MT fluoresced at about 20% of the expected intensity. Although Zinquin fluoresces with all cytosolic Zn, caution is required when comparisons are made between samples with different concentrations of MT. This limitation was demonstrated by staining liver slices from adjuvant-treated rats where MT was increased 24-fold, intracellular Zn by 77%, but Zinquin fluorescence by only 19% above controls. Nevertheless, Zinquin should prove to be a useful tool for studying the distribution of Zn in living cells.
锌喹啉[乙基(2-甲基-8-对甲苯磺酰胺基-6-喹啉氧基)乙酸酯]是一种新型细胞内锌荧光团，用于揭示和测量金属硫蛋白(MT)诱导前后培养的大鼠肝细胞中的锌。肝细胞呈现强烈的核外荧光。用锌、地塞米松和白细胞介素-6联合培养，细胞内MT增加24倍，锌增加3倍，锌喹啉荧光比对照值增加约2倍。锌喹啉荧光与细胞总锌(r = 0.747)、可交换锌(r = 0.735)、可溶性胞质锌(r = 0.669)和MT(r = 0.666)呈降序相关。在Sephadex G-75柱色谱之前，当锌喹啉与肝脏蛋白质的胞质部分一起孵育时，它会与游离的、结合MT的和蛋白质结合的锌一起发出荧光。尽管高分子质量蛋白质结合的锌仅使荧光略有减弱，但在锌喹啉存在下MT降解了60%。未降解的锌-MT发出的荧光强度约为预期强度的20%。尽管锌喹啉能与所有胞质锌发出荧光，但在比较不同MT浓度的样品时需要谨慎。在用佐剂处理的大鼠肝脏切片染色中证明了这一局限性，其中MT增加了24倍，细胞内锌增加了77%，但锌喹啉荧光仅比对照增加了19%。然而，锌喹啉应被证明是研究活细胞中锌分布的有用工具。
