Engel J, Donath E
Department of Biology, Division of Biophysics, Humboldt University, Berlin, F.R.G.
Biochim Biophys Acta. 1991 Apr 26;1064(1):155-61. doi: 10.1016/0005-2736(91)90422-5.
Bovine chromaffin granules were treated with the ionophores nigericin or A23187 in sucrose solutions with the pH varying from 4.7 to 7.0. Nigericin and A23187 induced osmotic lysis of the granules in sucrose solutions at pH values below 5.8, but not at physiological pH. This effect is explained by a progressive protonation of the acidic chromogranins induced by the ionophore-promoted exchange of internal potassium- and calcium ions for external protons. The results support the view that the interactions between catecholamines and ATP with chromogranins play a significant role in osmotic pressure reduction of the granule interior.
将牛嗜铬颗粒在蔗糖溶液中用离子载体尼日利亚菌素或A23187处理，蔗糖溶液的pH值在4.7至7.0之间变化。在pH值低于5.8的蔗糖溶液中，尼日利亚菌素和A23187会诱导颗粒发生渗透裂解，但在生理pH值下则不会。这种效应可以通过离子载体促进内部钾离子和钙离子与外部质子交换所诱导的酸性嗜铬粒蛋白的逐渐质子化来解释。这些结果支持了这样一种观点，即儿茶酚胺和ATP与嗜铬粒蛋白之间的相互作用在降低颗粒内部渗透压方面起着重要作用。
