These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Organophosphate inhibitors. The stereospecificity of hydrolysis of methyl n-butyl p-nitrophenyl phosphate by serum phosphotriesterases (EC 3.1.1.2) and by acetylcholinesterases (EC 3.1.1.7).
    Author: Dudman NP, de Jersey J, Zerner B.
    Journal: Biochim Biophys Acta; 1977 Mar 15; 481(1):127-39. PubMed ID: 191080.
    Abstract:
    A chiral phosphotriester, methyl n-butyl p-nitrophenyl phosphate was used to determine the stereospecificity of hydrolysis catalysed by serum phosphotriesterases (aryl-ester hydrolases, EC 3.1.1.2) from horse, ox and rabbit. Each enzyme hydrolysed the (-)-enantiomer more quickly. The same phosphate was used to inhibit acetycholinesterase (acetycholine hydrolase, EC 3.1.1.7) from ox, rabbit and electric eel, and in each case, the (+)-enantiomer caused more rapid inhibition. Serum phosphotriesterase did not catalyse the dephosphorylation of dialkyphosphoryl-acetylcholinesterase or dialkylphosphoryl-carboxylesterase. Levels of serum phosphotriesterase in rabbits which received sub-lethal injections of the phosphotriester remained unchanged after one or several injections. In the same rabbits, the levels of blood acetylcholinesterase fell sharply following injections, but normal values were regained in 2-8 days. Serum phosphotriesterases seem incapable either of preventing acute phosphotriester poisoning or of regenerating active enzyme from phosphorylated acetylcholinesterase. However, phosphotriesterases would act in cases of chronic exposure by catalysing the hydrolysis of such organophosphate poisons as remain in the blood.
    [Abstract] [Full Text] [Related] [New Search]