Saha A K, Das S, Glew R H, Gottlieb M
J Clin Microbiol. 1985 Sep;22(3):329-32. doi: 10.1128/jcm.22.3.329-332.1985.
Leishmania donovani promastigotes produce large quantities of two distinct acid phosphatases; a tartrate-resistant enzyme is localized to the external surface of the plasma membrane, and a tartrate-sensitive enzyme is secreted into the growth medium. It was shown previously that preincubation of human neutrophils and macrophages with the tartrate-resistant phosphatase markedly reduced the ability of these host cells to produce superoxide anions in response to stimulation with the activator formyl-methionyl-leucyl-phenylalanine. The possibility that the cell surface acid phosphatase or the phosphatase that is secreted into the extracellular fluid might compromise other host cell functions, especially intracellular ones, depends on the ability of the enzyme to resist exposure to toxic oxygen metabolites (e.g., superoxide anion, hydrogen peroxide, hypochlorite) generated by phagocytic cells. In the present report, we show that both leishmanial acid phosphatases were relatively resistant to inactivation by oxygen metabolites. At pH 5.5, the activity of the tartrate-resistant phosphatase was reduced 50% by incubation for 1 h with each of the following: 30 mM O2-, 500 mM hydrogen peroxide, and 6 mM hypochlorite ion. These concentrations are many fold greater than the concentrations of these substances that are generated by stimulated polymorphonuclear phagocytes. The tartrate-sensitive acid phosphatase differed markedly from the tartrate-resistant phosphatase in that the former was essentially insensitive to even very high concentrations of superoxide anion and hydrogen peroxide. Furthermore, 50% inactivation of the tartrate-sensitive leishmanial phosphatase required exposure to 35 mM hypochlorite for 30 min. These results indicate that the catalytic potential of these two leishmanial acid phosphatases probably survives exposure to toxic oxygen metabolites generated by neutrophils and macrophages.
杜氏利什曼原虫前鞭毛体产生大量两种不同的酸性磷酸酶；一种抗酒石酸的酶定位于质膜的外表面，而一种对酒石酸敏感的酶分泌到生长培养基中。先前已表明，用人中性粒细胞和巨噬细胞与抗酒石酸磷酸酶预孵育可显著降低这些宿主细胞在受到激活剂甲酰甲硫氨酰亮氨酰苯丙氨酸刺激时产生超氧阴离子的能力。细胞表面酸性磷酸酶或分泌到细胞外液中的磷酸酶可能损害其他宿主细胞功能，尤其是细胞内功能的可能性，取决于该酶抵抗吞噬细胞产生的有毒氧代谢产物（如超氧阴离子、过氧化氢、次氯酸盐）的能力。在本报告中，我们表明两种利什曼原虫酸性磷酸酶对氧代谢产物的失活都具有相对抗性。在pH 5.5时，用以下每种物质孵育1小时，抗酒石酸磷酸酶的活性降低50%：30 mM超氧阴离子、500 mM过氧化氢和6 mM次氯酸根离子。这些浓度比受刺激的多形核吞噬细胞产生的这些物质的浓度高许多倍。对酒石酸敏感的酸性磷酸酶与抗酒石酸磷酸酶明显不同，前者即使对非常高浓度的超氧阴离子和过氧化氢也基本不敏感。此外，对酒石酸敏感的利什曼原虫磷酸酶50%失活需要暴露于35 mM次氯酸盐30分钟。这些结果表明，这两种利什曼原虫酸性磷酸酶的催化潜能在暴露于中性粒细胞和巨噬细胞产生的有毒氧代谢产物后可能仍然存在。
