Redistribution and characterization of (H+ + K+)-ATPase membranes from resting and stimulated gastric parietal cells.
Redistribution and characterization of (H+ + K+)-ATPase membranes from resting and stimulated gastric parietal cells.
复制标题
静息和刺激胃壁细胞的 (H K )-ATP 酶膜的重新分布和表征。
DOI：
10.1042/bj2310641
复制
发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Forte,JG
中科院分区：
文献类型：
--
作者：
Hirst,BH;Forte,JG
当从静息壁细胞分离时，大部分（H+ + K+）-ATP酶活性在微粒体组分中恢复。这些微粒体囊泡表现出较低的K+渗透性，因此添加缬氨霉素导致（H+ + K+）-ATP酶活性和质子积累的显著刺激。当从刺激的壁细胞分离时，（H+ + K+）-ATP酶重新分布到更大，更致密的囊泡中：刺激相关（s.a.）囊泡S.A.囊泡显示出增加的K+渗透性，使得在低K+浓度下观察到最大的（H+ + K+）-ATP酶和质子积累活性，并且在添加缬氨霉素时没有发生活性增强。（H+ + K+）-ATP酶亚细胞分布的变化与壁细胞、微粒体和s.a.囊泡分别来源于细胞内小管囊泡和顶端质膜。（H+ + K+）-ATP酶总活性为静息组织的64%。因此，我们测试了s.a.囊泡s.a.的透化具有辛基葡糖苷的囊泡使（H+ + K+）-ATP酶活性增加2倍以上。潜在的（H+ + K+）-ATP酶活性对高胰蛋白酶条件（使胃微粒体中的所有活性失活）具有抵抗力。约20%的非潜伏性（H+ + K+）-ATP酶活性也对胰蛋白酶消化具有抗性。我们解释这些结果表明，s.a.囊泡，约。55%具有右侧向外的方向并且不渗透ATP，10%具有右侧向外的方向并且可渗透ATP，并且35%具有内侧向外的方向。
When isolated from resting parietal cells, the majority of the (H+ + K+)-ATPase activity was recovered in the microsomal fraction. These microsomal vesicles demonstrated a low K+ permeability, such that the addition of valinomycin resulted in marked stimulation of (H+ + K+)-ATPase activity, and proton accumulation. When isolated from stimulated parietal cells, the (H+ + K+)-ATPase was redistributed to larger, denser vesicles: stimulation-associated (s.a.) vesicles. S.a. vesicles showed an increased K+ permeability, such that maximal (H+ + K+)-ATPase and proton accumulation activities were observed in low K+ concentrations and no enhancement of activities occurred on the addition of valinomycin. The change in subcellular distribution of (H+ + K+)-ATPase correlated with morphological changes observed with stimulation of parietal cells, the microsomes and s.a. vesicles derived from the intracellular tubulovesicles and the apical plasma membrane, respectively. Total (H+ + K+)-ATPase activity recoverable from stimulated gastric mucosa was 64% of that from resting tissue. Therefore, we tested for latent activity in s.a. vesicles. Permeabilization of s.a. vesicles with octyl glucoside increased (H+ + K+)-ATPase activity by greater than 2-fold. Latent (H+ + K+)-ATPase activity was resistant to highly tryptic conditions (which inactivated all activity in gastric microsomes). About 20% of the non-latent (H+ + K+)-ATPase activity was also resistant to trypsin digestion. We interpret these results as indicating that, of the s.a. vesicles, approx. 55% have a right-side-out orientation and are impermeable to ATP, 10% right-side-out and permeable to ATP, and 35% have an inside-out orientation.