Young P R, Synder W R, McMahon R F
Department of Chemistry, University of Illinois, Chicago 60680.
Biochim Biophys Acta. 1992 Jun 24;1121(3):297-300. doi: 10.1016/0167-4838(92)90160-f.
Polyamines, alkyldiammonium and alkyldisulfonium salts, inhibit the Clostridium perfringens phospholipase C-catalyzed hydrolysis of 1-S-phosphocholine-2-O-hexadecanoyl-1-mercapto-2-ethanol (1) at pH 7.5, 37 degrees C, mu = 1.0 with KCl. Simple saturation kinetics are observed as both 1 and [Ca2+] are varied and simple linear inhibition is observed. The data are consistent with a non-competitive mechanism that involves binding of the inhibitors to free enzyme, E.[Ca2+] and E.[Ca2+].[S]; the inhibition constants for decamethylenebis(trimethylammonium) and decamethylenebis(dimethylsulfonium) bromides are 90 and 0.28 mM, respectively. It is suggested that the enhanced inhibition by the alkyldisulfonium salts results from more favorable equilibrium constants for contact ion-pair formation or from the formation of tetracoordinate sulfuranes.
多胺、烷基二铵盐和烷基二锍盐在pH 7.5、37℃、μ = 1.0（含KCl）的条件下，可抑制产气荚膜梭菌磷脂酶C催化的1 - S - 磷酸胆碱 - 2 - O - 十六烷酰基 - 1 - 巯基 - 2 - 乙醇（1）的水解反应。当1和[Ca2+]变化时，观察到简单的饱和动力学，且呈现简单的线性抑制。这些数据符合非竞争性机制，该机制涉及抑制剂与游离酶E、E·[Ca2+]和E·[Ca2+]·[S]的结合；十亚甲基双（三甲基铵）和十亚甲基双（二甲基锍）溴化物的抑制常数分别为90 mM和0.28 mM。有人提出，烷基二锍盐增强的抑制作用源于接触离子对形成的更有利平衡常数或四配位硫烷的形成。
