Bingham M J, Ong T J, Ingledew W J, McArdle H J
Department of Child Health, Ninewells Hospital and Medical School, University of Dundee, United Kingdom.
Am J Physiol. 1996 Nov;271(5 Pt 1):G741-6. doi: 10.1152/ajpgi.1996.271.5.G741.
The Wilson disease adenosinetriphosphatase (ATPase; ATP7B) is believed to bind copper as Cu(I). We provide evidence to suggest that the ATPase actually transports Cu as Cu(II). When the copper is presented to rat liver microsomes as Cu(I), virtually all uptake is ATP independent. If the copper is presented as copper oxalate [Cu(II)], total uptake is reduced to approximately 10% of Cu(I) levels, but ATP-dependent uptake rises, both as a proportion of total uptake and in absolute terms. The reducing agent vitamin C and the Cu(I) chelator bathocuproine both override the effect of oxalate. The data indicate that there are two transporters in the microsomes, an ATP-independent Cu(I) transporter and an ATP-dependent Cu(II) pump. The activity of the Cu(I) transporter correlates most strongly with alkaline phosphatase, suggesting that it is derived from plasma membrane contamination. Cu(II) ATP-dependent transport correlates only with beta-1, 4-galactosyltransferase, which indicates that it is located in the Golgi apparatus.
威尔逊病三磷酸腺苷酶（ATP酶；ATP7B）被认为以Cu（I）形式结合铜。我们提供的证据表明，该ATP酶实际上以Cu（II）形式转运铜。当铜以Cu（I）形式提供给大鼠肝微粒体时，几乎所有的摄取都不依赖于ATP。如果铜以草酸铜[Cu（II）]形式提供，总摄取量降至Cu（I）水平的约10%，但ATP依赖性摄取增加，无论是占总摄取量的比例还是绝对值。还原剂维生素C和Cu（I）螯合剂bathocuproine都能消除草酸盐的影响。数据表明，微粒体中有两种转运体，一种是不依赖ATP的Cu（I）转运体，另一种是依赖ATP的Cu（II）泵。Cu（I）转运体的活性与碱性磷酸酶的相关性最强，表明它源自质膜污染。Cu（II）依赖ATP的转运仅与β-1,4-半乳糖基转移酶相关，这表明它位于高尔基体中。
