Scherman D, Soumarmon A, Henry J P
Biochimie. 1986 Dec;68(12):1303-9. doi: 10.1016/s0300-9084(86)80083-9.
Chromaffin granule membranes were incubated in the presence of low ATP concentrations, at low temperature. A phosphorylated compound was rapidly formed which was stable in 10% trichloroacetic acid at 0 degree C. The lability of this compound in the presence of hydroxylamine or hot trichloroacetic acid indicated an acylphosphate, i.e., an ATPase phosphointermediate. Vanadate but not N-ethylmaleimide inhibited the formation of this derivative. Since the ATP-dependent generation of a transmembrane potential in chromaffin granule vesicles by the H+-pump was inhibited by N-ethylmaleimide but not by vanadate, the acylphosphate should not be associated with the H+-pump, i.e. ATPase I. We suggest that it is associated with ATPase II, an ATPase of unknown function present in chromaffin granule membrane preparations. This hypothesis is supported by the fact that ATPase II is vanadate sensitive and has a molecular mass of 140 kDa, properties similar to those of the phosphorylated intermediate.
嗜铬粒细胞膜在低温及低ATP浓度条件下进行孵育。迅速形成了一种磷酸化化合物，该化合物在0℃的10%三氯乙酸中稳定。此化合物在羟胺或热三氯乙酸存在下的不稳定性表明它是一种酰基磷酸酯，即ATP酶磷酸中间体。钒酸盐而非N - 乙基马来酰亚胺抑制了这种衍生物的形成。由于嗜铬粒小泡中由H⁺泵产生的依赖ATP的跨膜电位被N - 乙基马来酰亚胺而非钒酸盐抑制，所以酰基磷酸酯不应与H⁺泵即ATP酶I相关联。我们认为它与ATP酶II相关，ATP酶II是存在于嗜铬粒细胞膜制剂中的一种功能未知的ATP酶。这一假设得到以下事实的支持：ATP酶II对钒酸盐敏感，分子量为140 kDa，其特性与磷酸化中间体相似。
