Dobrovoljc K, Falnoga I, Bulog B, Tusek-Znidaric M, Scancar J
Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, Ljubljana 1000, Slovenia.
Comp Biochem Physiol C Toxicol Pharmacol. 2003 Jul;135C(3):285-94. doi: 10.1016/s1532-0456(03)00118-2.
The presence of metallothionein (MT) and the subcellular distribution of copper, zinc and cadmium were investigated in livers of two neotenic salamanders, Proteus anguinus and Necturus maculosus. In P. anguinus, caught in the wild, hepatic MTs were present as a single isoform of (Zn, Cu, Cd)-thioneins, whose molecular weight was estimated to be approximately 12000 by size exclusion chromatography. The percentage of zinc and cadmium was higher in the cytosol and of copper in the pellet. Cytosolic cadmium was almost exclusively associated with MTs (80%), while zinc and copper were also present in the regions of higher-molecular weight proteins. In laboratory bred N. maculosus, MTs were isolated from the liver cytosol and extract of the pellet as (Cu, Zn)- and (Zn, Cu)-thioneins, respectively. According to the low amount of copper extracting from liver pellets of N. maculosus, the presence of water insoluble aggregated forms of Cu-thioneins should be checked in further investigations.
研究了两种幼态蝾螈——盲螈（Proteus anguinus）和斑泥螈（Necturus maculosus）肝脏中金属硫蛋白（MT）的存在情况以及铜、锌和镉的亚细胞分布。在野外捕获的盲螈中，肝脏MTs以单一的（锌、铜、镉）硫蛋白异构体形式存在，通过尺寸排阻色谱法估计其分子量约为12000。锌和镉在胞质溶胶中的百分比更高，而铜在沉淀中的百分比更高。胞质溶胶中的镉几乎完全与MTs结合（80%），而锌和铜也存在于高分子量蛋白质区域。在实验室饲养的斑泥螈中，分别从肝脏胞质溶胶和沉淀提取物中分离出MTs，分别为（铜、锌）硫蛋白和（锌、铜）硫蛋白。根据从斑泥螈肝脏沉淀中提取的铜量较低这一情况，在进一步研究中应检查是否存在水不溶性的铜硫蛋白聚集形式。
