title: [Inactivation of soman by beta-cyclodextrin].
abstract: Soman (pinacolyl methylphosphonofluoridate), a mixture of four stereoisomers, is inactivated appreciably in Tris buffer, pH 7.40, mu = 0.155 at 25 degrees C by beta-cyclodextrin (cycloheptaamylose, beta-CD). Under these conditions, the dissociation constant Kd of the 1:1 complex formed by beta-CD and soman and the rate constant k2 for the phosphonylation of beta-CD by soman are (0.53 +/- 0.05)mM and (5.9 +/- 0.6) X 10(-2) min-1 respectively. It results that the inactivation of soman by the mono-anion of beta-CD is about 2,600 times faster than the hydrolysis of soman by the hydroxide ion. The inactivation of both P(-) isomers of soman by beta-CD proceeds apparently at the same rate but both P(+) isomers react more slowly. Thus the interaction is stereospecific. The inactivation of soman by beta-CD appears to be as fast in human plasma in vitro as in Tris buffer.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003505:Cyclodextrins / Q000378:metabolism* / Q000494:pharmacology; D003912:Dextrins / Q000378:metabolism*; D007700:Kinetics; D012999:Soman / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013213:Starch / Q000378:metabolism*; D013237:Stereoisomerism; D047392:beta-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D003912:Dextrins; D047392:beta-Cyclodextrins; D013213:Starch; D012999:Soman; C031215:betadex
vernacular_title: Inactivation du soman par la beta-cyclodextrine.