Beinborn M, Netz S, Staar U, Sewing K F
Abteilung Allgemeine Pharmakologie, Medizinische Hochschule Hannover, F.R.G.
Eur J Pharmacol. 1988 Mar 1;147(2):217-26. doi: 10.1016/0014-2999(88)90780-7.
[3H]Prostaglandin E2 (PGE2) binding sites were 10-fold enriched from a porcine fundic mucosal homogenate by differential centrifugation and subsequent discontinuous sucrose gradient separation. PGE2 bound with an activation energy of 66 kJ/mol to a single class of sites with an affinity of 1.5 +/- 0.4 nM and a capacity of 274 +/- 76 fmol/mg protein. There was no indication for any cooperativity between the binding sites. Kinetic analysis revealed a kon of 3 x 10(5) M x s-1 at 30 degrees C and pH 5.5. Dissociation was biphasic with an initial rapid (koff = 10(-3) s-1) and a subsequent slower phase (koff = 4 X 10(-5) s-1), presumably reflecting the existence of two interchangeable forms of [3H]PGE2 binding sites. The rank order of affinity for other prostanoids (PGE2 greater than PGE1 greater than PGA2 greater than iloprost (PGI2 derivative) greater than PGF2 alpha greater than PGB2 greater than PGD2) is discussed against the background of the recently postulated E-type receptors in the stomach.
通过差速离心和随后的不连续蔗糖梯度分离，从猪胃底黏膜匀浆中富集了10倍的[3H]前列腺素E2（PGE2）结合位点。PGE2以66 kJ/mol的活化能与一类位点结合，其亲和力为1.5±0.4 nM，容量为274±76 fmol/mg蛋白质。结合位点之间没有协同作用的迹象。动力学分析显示，在30℃和pH 5.5条件下，kon为3×10(5) M×s-1。解离是双相的，初始快速（koff = 10(-3) s-1），随后较慢（koff = 4×10(-5) s-1），这可能反映了[3H]PGE2结合位点存在两种可互换的形式。根据最近在胃中假定的E型受体的背景，讨论了对其他前列腺素（PGE2＞PGE1＞PGA2＞伊洛前列素（PGI2衍生物）＞PGF2α＞PGB2＞PGD2）的亲和力排序。
