We have located links that may give you full text access.
Characterization of asymmetric fluorogenic phosphonates as probes for developing organophosphorus hydrolases with broader stereoselectivity.
Chemico-biological Interactions 2008 September 26
Organophosphorus hydrolases (OPH) such as mammalian plama paraoxonase (PON1) detoxify asymmetric toxic organophosphorus (OP) nerve agents by preferentially hydrolyzing the less toxic P(+) optical isomer. In order to develop new OPHs with broader stereoselectivity we have prepared a series of asymmetric fluorogenic organophosphonates (Flu-OPs). Such Flu-OPs may serve as molecular probes for screening large libraries of OP hydrolases during directed evolution. Flu-OPs were prepared as methylphosphonates (MPs) diesters containing either ethyl (E), isopropyl (I), cyclohexyl (C) or pinacolyl (P) groups that are structural congeners of the nerve agents VX, sarin, cyclosarin and soman, respectively. The second ester bond was formed with fluorescent moieties that are either 3-cyano-4-methyl-7-hydroxy coumarin (MeCyC) or 1,3-dichloro-7-hydroxy 9,9-dimethyl-9H-acridin-2-one (DDAO). To further characterize the Flu-OPs as surrogates of their respective nerve agents, we have studied the reactivation of Flu-OP-inhibited AChE using 2-PAM and toxogonin (TOX). AChE was 90-95% inhibited by all Flu-OPs (0.36-0.9(M) and then was reactivated by either 2-PAM or TOX. TOX caused a more rapid reactivation than 2-PAM with the following rank order; EMP>IMP>CMP. TOX was also shown to be a better reactivator than 2-PAM for AChE inhibited by the nerve agents VX and cyclosarin. PMP-AChE could not be reactivated by either TOX or 2-PAM, similarly to aging of PMP-AChE formed by inhibition with soman. Racemic CMP-MeCyC was used for screening two new PON1 variants from a neutral library of PON1. These multiple mutation variants include replacement of active site amino acid residues. Neither mutation in these new variants appeared in PON1 variants previously discovered by directed evolution using symmetric Flu-OP. Detoxification rate of cylcosarin by these new PON1 variants was rather slow indicating the need to further screen PON1 clones using optically active Flu-OPs. Therefore, we have separated enzymatically the P(-) enantiomer of CMP-MeCyC and determined its 98% purity using chiral HPLC.
Full text links
Related Resources
Trending Papers
Interstitial Lung Disease: A Review.JAMA 2024 April 23
Review article: Recent advances in ascites and acute kidney injury management in cirrhosis.Alimentary Pharmacology & Therapeutics 2024 March 26
Executive Summary: State-of-the-Art Review: Unintended Consequences: Risk of Opportunistic Infections Associated with Long-term Glucocorticoid Therapies in Adults.Clinical Infectious Diseases 2024 April 11
Clinical practice guidelines on the management of status epilepticus in adults: A systematic review.Epilepsia 2024 April 13
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app