Chettur G, DeFrank J J, Gallo B J, Hoskin F C, Mainer S, Robbins F M, Steinmann K E, Walker J E
IIT Research Institute, Chicago, Illinois 60616.
Fundam Appl Toxicol. 1988 Oct;11(3):373-80. doi: 10.1016/0272-0590(88)90103-0.
An enzyme that hydrolyzes soman (1,2,2-trimethylpropyl methylphosphonofluoridate) and two other phosphonofluoridates, but does not hydrolyze DFP (diisopropylphosphorofluoridate), has been partially purified from a rod-shaped spore-forming gram-positive OT (obligate thermophilic) bacterium. The enzyme shows a marked Mn2+ stimulation, and in this and its substrate preference does not resemble the organophosphorus acid anhydrolase (sometimes termed DFPase) found in squid. Like the squid enzyme, it is not inhibited by mipafox (N,N'-diisopropylphosphordiamidofluoridate), is not inactivated by ammonium sulfate, and does hydrolyze the acetylcholinesterase-inhibitory pair of diastereoisomers of soman as well as the relatively noninhibitory pair, thus detoxifying soman. In these three properties the OT enzyme does not resemble the ubiquitous organophosphorus acid anhydrolase often purified from mammalian and bacterial sources by cold ethanol fractionation. Thus this phosphono-specific OT enzyme may have a natural substrate and a physiological role distinct from other organophosphorus acid anhydrolases.
一种能水解梭曼（1,2,2-三甲基丙基甲基膦酰氟）和其他两种膦酰氟，但不能水解二异丙基氟磷酸酯（DFP）的酶，已从一种杆状、形成芽孢的革兰氏阳性嗜热菌（专性嗜热菌）中部分纯化出来。该酶表现出明显的锰离子刺激作用，并且在这方面及其底物偏好上与在鱿鱼中发现的有机磷酸酐酶（有时称为DFP酶）不同。与鱿鱼酶一样，它不受丙胺氟磷（N,N'-二异丙基磷酰二氨基氟化物）抑制，不被硫酸铵灭活，并且确实能水解梭曼的乙酰胆碱酯酶抑制性非对映异构体对以及相对无抑制作用的对映异构体对，从而使梭曼解毒。在这三个特性方面，嗜热菌酶与通常通过冷乙醇分级从哺乳动物和细菌来源纯化的普遍存在的有机磷酸酐酶不同。因此，这种膦酸特异性嗜热菌酶可能具有与其他有机磷酸酐酶不同的天然底物和生理作用。
