Singh A K
Toxicology. 1986 Dec 15;42(2-3):143-56. doi: 10.1016/0300-483x(86)90005-3.
Acephate pre-exposure provided protection against the inhibition of RBC and brain acetylcholinesterase (AChE), and plasma cholinesterase (ChE) activities in rats exposed to both acephate and methamidophos. In vitro addition of acephate to AChE prior to or with methamidophos also provided complete protection against AChE inhibition by methamidophos. When acephate was added to the enzyme after methamidophos, its protective effect decreased with increasing time between the additions. Since acephate has greater affinity than does methamidophos for the AChE active site (Singh, A.K., Toxicol. Appl. Pharmacol., 81 (1985) 302), it is proposed that acephate provided protection by binding with the AChE active site and, therefore, preventing methamidophos from binding with the enzyme. It is also proposed that acephate prevented the initial competitive binding of methamidophos to the AChE active site and delayed the initial sequence of events essential for phosphorylation of AChE.
预先接触乙酰甲胺磷可保护大鼠免受乙酰甲胺磷和甲胺磷联合暴露所致的红细胞及脑乙酰胆碱酯酶（AChE）抑制，以及血浆胆碱酯酶（ChE）活性抑制。在体外，于甲胺磷之前或与甲胺磷同时向AChE中添加乙酰甲胺磷，也可完全保护AChE免受甲胺磷抑制。当在甲胺磷之后向酶中添加乙酰甲胺磷时，其保护作用会随着添加时间间隔的增加而降低。由于乙酰甲胺磷对AChE活性位点的亲和力比甲胺磷更高（辛格，A.K.，《毒理学与应用药理学》，81（1985）302），因此推测乙酰甲胺磷通过与AChE活性位点结合来提供保护，从而阻止甲胺磷与该酶结合。还推测乙酰甲胺磷可阻止甲胺磷对AChE活性位点的初始竞争性结合，并延迟AChE磷酸化所必需的初始事件序列。
