Sekler I, Remis D, Gimmler H, Pick U
Department of Biochemistry, Weizmann Institute of Science, Rehovot, Israel.
Biochim Biophys Acta. 1993 Apr 5;1142(1-2):88-92. doi: 10.1016/0005-2728(93)90088-w.
The acid-activated sulfhydryl reagent omeprazole inhibits light-induced H+ secretion at pH 1 in cells of the halotolerant alga Dunaliella acidophila. Plasma-membrane vesicles, prepared from omeprazole-treated cells, have impaired vanadate-sensitive ATPase and ATP-induced H+ uptake activities. Omeprazole inhibits ATPase activity also in isolated plasma-membrane vesicles. The inhibition is enhanced at acidic pH and can be prevented by protonophores indicating that it is promoted by internal acidification of the vesicles. Mercaptoethanol partially reverses omeprazole inhibition. ADP does not afford protection against omeprazole but it does protect against inhibition by N-ethylmaleimide, indicating that these reagents modify different sulfhydryl groups. It is suggested that omeprazole blocks SH groups of the D. acidophila plasma-membrane H(+)-ATPase, which face the outer side of the cell.
酸活化巯基试剂奥美拉唑可抑制耐盐藻类嗜酸杜氏藻细胞在pH 1时光诱导的H⁺分泌。从经奥美拉唑处理的细胞制备的质膜囊泡，其钒酸盐敏感的ATP酶和ATP诱导的H⁺摄取活性受损。奥美拉唑在分离的质膜囊泡中也能抑制ATP酶活性。在酸性pH条件下，这种抑制作用增强，质子载体可阻止其抑制作用，这表明囊泡的内部酸化促进了该抑制作用。巯基乙醇可部分逆转奥美拉唑的抑制作用。ADP不能保护细胞免受奥美拉唑的抑制，但它能保护细胞免受N - 乙基马来酰亚胺的抑制，这表明这些试剂修饰的是不同的巯基。有人提出，奥美拉唑会阻断嗜酸杜氏藻质膜H⁺ - ATP酶面向细胞外侧的巯基。
