Diethyl p-nitrophenyl phosphate

Diethyl p-nitrophenyl phosphate (E-600) is an odorless reddish-yellow oil which... 

Diethyl p-nitrophenyl phosphate, the oxygen analog of parathion, was investigated to ascertain whether it would interfere, if present, in the determination of parathion. It was found, however, under the conditions used in this method to have a decomposition potential of —0.37 volt and a half-wave potential of —0.47 volt. 

List of Abbreviations ACh, acetylcholine DNPP, diethyl-p-nitrophenyl phosphate GABA, y-amino-butyric acid nAGhR, nicotinic acetylcholine receptor... 

A hydroxoaqua copper complex containing N, N, N, A -tetramethyl-1,2-diamino-ethane (250) is an excellent catalyst for the hydrolysis of sarin, O-isopropyl methylphosphonofluoridate (251), and diethyl p-nitrophenyl phosphate (252 R = Et). The mechanism of the reaction probably involves bound hydroxide attacking the phosphoryl group with concomitant electrophilic catalysis by copper. 

Diethyl p-nitrophenyl phosphate, see Parathion 0,5-Diethyl O-4-nitrophenyl phosphorothioate, see Parathion... 

Inhibition of lipases, both by the substrate or the product, has been observed. In alcoholysis of methyl propanoate with n-propanol catalyzed by Candida antarctica lipase B (CALB), the alcohol was found to inhibit the enzyme resulting in a deadend complex [21]. Phosphate- and phosphonate-conlaining inhibitors are known to inhibit proteases. Studies of the inhibition of CALB have shown inhibition by diethyl p-nitrophenyl phosphate. The inactivation of the enzyme was caused by covalent binding of diethyl p-nitrophenyl phosphate in the active site [22]. 

Diethyl p-nitrophenyl phosphate (DNPP) N-acetyl-1 tryptophan ethyl ester (NATrpEE) Sugatani et. al. 1987... 

Rhizomucor miehei with diethyl p-nitrophenyl phosphate... 

The inhibition of hLAL by boronic acids and diethyl p-nitrophenyl phosphate (Sando and Rosenbaum, 1985 G. N. Sando and H. L. Brockman, unpublished, cited by Anderson and Sando, 1991) indicates that hLAL is a serine hydrolase. Two lipase/esterase consensus pentapep-tides, G-X-S-X-G, are found, but only one of them appears to be consistent with the packing requirements of the )8-eSer-a nucleophilic motif (see above). Susceptibility of the enzyme to sulfhydryl reagents, and the requirement of thiols for the stability of purified hLAL, prompted Anderson and Sando (1991) to propose that a cysteine residue, or rather a Cys/Ser couple, may be involved in an internal transacylation reaction. It must be pointed out, however, that hLAL has all three cysteines of the gastric enzyme (as well as six additional ones), and so the inhibitory Cys is also there. The same argument proposed herein with respect to hGL, i.e., that a free cysteine is topologically close to the active site, also holds for hLAL. 

In Fig. 9.4 are depicted the chemical structures of all inhibitors we will discuss diethyl p-nitrophenyl phosphate (Egoo), orlistat and O-mefhyl-O-(p-nitrophenyl) n-undecylphosphonate (Cll-P). In order to study the effects of these reagents, which can in principle modify covalently several essential amino acid residues of the lipases, we have proposed four different methods [50-52], depending upon the order of addition of lipase, substrate and inhibitor (Fig. 9.5). 

Desnuelle, P., Sarda, L. and Ailhaud, G. (1960) Inhibition de la lipase pancreatique par le diethyl-p-nitrophenyl phosphate en emulsion. Biochim. Biophys. Acta 37, 570-571... 

Inhibition of pancreatic lipase by mixed micelles of diethyl p-nitrophenyl phosphate and the bile salts. Biochim. Biophys. Acta 530, 227-235... 

Aldridge, W.N. 1953b, Serum esterases. II. An enz3mie hydrolysing diethyl p-nitrophenyl phosphate (E600) and its identity with the A-esterase of mammahan sera, Biochem. J., vol. 53, no. 1, pp. 117-124. Aldridge, W.N. and Reiner, E. 1972, Enzyme Inhibitors as Substrates, North Holland, Amsterdam. 

AlO. Aldridge, W. N., and Davison, A. N., The inhibition of erythrocyte cholinesterase by tri-esters of phosphoric acid, I. Diethyl p-nitrophenyl phosphate (E600) and its analogues. Biochem. ]. 51, 62-70 (1952). 

The first example of this most important group of phosphorus esters, diethyl-p-nitrophenyl phosphate (paraoxon, 15), was prepared by Schrader (1948a) by the reaction of diethyl phosphorochloridate (16) with sodium p-nitrophenolate ... 

Diethyl S-(2-(ethylthio)ethyl) phosphorodithloate Diethyl-p-nitrophenyl phosphate 0,0-Diethyl 0-pyrazinyl phosphoro-thioate... 

In addition to activation by heparin, lipoprotein lipase requires the addition of cations and of a fatty acid acceptor such as serum albiunin (254). The enzyme is inhibited by high concentrations of NaCl (M), 5% sodium taurocholate and 5% protamine (376, 393), sodium fluoride and diethyl p-nitrophenyl phosphate (394), and polyamino acids (395). Particle-free extracts of human or rabbit spleen, kidney, and liver are also stated to be inhibitory (396). 

Organophosphorus reagents that inhibit hydrolases (serine hydrolases) diethyl p-nitrophenyl phosphate (paraoxon) diisopropyl phosphofluoridate (DFP) dimethyl(dichlorovinyl) phosphate (dichlovos) O -methylphosphoramidothioate 3-hydroxy-N-methyl-cis-crotonamide dimethylphosphate tetraethyl pyrophosphate (TEPP)... 

Recent theoretical studies employing quantum mechanics/molecular mechanics (QM/MM) potentials have confirmed that alkaline hydrolysis of 0,0,-diethyl p-nitrophenyl phosphate (paraoxon) takes place through an associative mechanism wherein the bond order of the leaving group is larger than the bond order of the phosphoms atom to the nucleophile. Moreover, the theoretical estimations of the free energy barriers and kinetic isotope effects agreed very well with the experimental values, more so than those by previous theoretical estimations. ... 

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