Phenyl phosphate 4-nitro

Schrader prepared the ester (38) in 60% yield by reaction of sodium p-nitrophenate with diethyl chlorophosphate, using xylene as solvent for the reaction. He made it, but in lower yields, from p-nitrophenol and diethyl chlorophosphate, using, respectively, pyridine and sodium cyanide as acceptors for hydrogen chloride. Schrader also prepared it in 96% yield by nitrating diethyl phenyl phosphate at 0° C. or below. Under the conditions he used, Schrader claims that the nitro group is directed to the para position. No yield is given for the diethyl phenyl phosphate, which he presumably made from sodium phenate and diethyl chlorophosphate. Diethyl chlorophosphate may be prepared in high yield (30) from diethyl phosphite and chlorine. 

Fig. 23 A plot of the observed pseudo-first-order rate constant for the methanolysis of 0.04mM HPNPP ( , left axis) catalyzed by 0.2mM35 2Zn(II) or 0.04mM methyl /j-nitro-phenyl phosphate (O, right axis) catalyzed by 0.4 mM 35 Zn(II) as a function of the [CH30-]/ [35 Zn(II)] ratio at 25 + 0.1 °C. Experiments done by pH jump method starting at a [CH30-]/ [35 Zn(II)] ratio of 1.0 (vertical dashed line, (pH = 9.5) and adding acid (left) or base (right). Reproduced with permission from ref. 95.

Nitration of diethyl AT-phenylphosphoramidate and diethyl phenyl phosphate in acetic anhydride or sulphuric acid yields considerable amounts of the m-nitro-... 

The pre/ivference for solvolysis of meta substituted esters such as m-nitro-phenyl phosphate and m-methoxybenzyl acetate was discovered by Havinga et and studied further by Zimmerman (equation 50). Radicals can be formed in these reactions, and there is some dispute as to whether radical pairs also lead to ion pairs (equation 50). ... 

While there have been a considerable number of structural models for these multinuclear zinc enzymes (49), there have only been a few functional models until now. Czamik et al. have reported phosphate hydrolysis with bis(Coni-cyclen) complexes 39 (50) and 40 (51). The flexible binuclear cobalt(III) complex 39 (1 mM) hydrolyzed bis(4-nitro-phenyl)phosphate (BNP-) (0.05 mM) at pH 7 and 25°C with a rate 3.2 times faster than the parent Coni-cyclen (2 mM). The more rigid complex 40 was designed to accommodate inorganic phosphate in the in-temuclear pocket and to prevent formation of an intramolecular ju.-oxo dinuclear complex. The dinuclear cobalt(III) complex 40 (1 mM) indeed hydrolyzed 4-nitrophenyl phosphate (NP2-) (0.025 mM) 10 times faster than Coni-cyclen (2 mM) at pH 7 and 25°C (see Scheme 10). The final product was postulated to be 41 on the basis of 31P NMR analysis. In 40, one cobalt(III) ion probably provides a nucleophilic water molecule, while the second cobalt(III) binds the phosphoryl group in the form of a four-membered ring (see 42). The reaction of the phosphomonoester NP2- can therefore profit from the special placement of the two metal ions. As expected from the weaker interaction of BNP- with cobalt(in), 40 did not show enhanced reactivity toward BNP-. However, in the absence of more quantitative data, a detailed reaction mechanism cannot be drawn. 

The enzymes commonly used are pure and have a high turnover number (48). They include horseradish peroxidase (with o-phenylene diamine as substrate which yields a yellow colored product, 2,2 azino-(3ethyl)-benzo-sulphonic acid gives green colored product, or tetramethyl benzidine gives a blue product) and alkaline phosphatase (with p-nitro phenyl phosphate as substrate to give a yellow /orange colored product). 

Solution of the appropriate substrate for the enzyme chosen (e.g., 1 mg/mL p-nitro-phenyl phosphate in 0.1 Mdiethanolamine-HCl, pH 9.8, for alkaline phosphatase conjugates 3,3, 5,5 -tetramethylbenzidine (TMB) or3,3 -diaminobenzidine (DAB) for horseradish peroxidase conjugates). 

The electrostatic model for the micellar effect on the hydrolysis of phosphate monoesters is also consistent with the results of inhibition studies (Bunton et al., 1968, 1970). The CTAB catalyzed hydrolysis of the dinitrophenyl phosphate dianions was found to be inhibited by low concentrations of a number of salts (Fig. 9). Simple electrolytes such as sodium chloride, sodium phosphate, and disodium tetraborate had little effect on the micellar catalysis, but salts with bulky organic anions such as sodium p-toluenesulfonate and sodium salts of aryl carboxylic and phosphoric acids dramatically inhibited the micelle catalysis by CTAB. From equation 14 and Fig. 10, the inhibitor constants, K, were calculated (Bunton et al., 1968) and are given in Table 9. The linearity of the plots in Fig. 10 justifies the assumption that the inhibition is competitive and that incorporation of an inhibitor molecule in a micelle prevents incorporation of the substrate (see Section III). Comparison of the value of for phenyl phosphate and the values of K for 2,4-and 2,6-dinitrophenyl phosphates suggests that nitro groups assist the... 

The fusion of purine with 1,2,3,5-tetra-O-acctyl-D-ribofuranose in the presence of bis(4-nitro-phenyl) phosphate gives mixtures of N9 and N7 purine nucleosides 11 and 12, respectively. 

In recent years, methods for the catalytic cleavage of the P-O bond in phosphate esters have been developed. It is now reported that a cyclic P-sheet peptide -based binuclear zinc (II) complex markedly accelerated the cleavage of the phosphodiester linkage of the RNA model substrate 2-hydroxypropyl p-nitro-phenyl phosphate (102) (Scheme 17). °... 

The properties of these two components or isoenzymes of rat liver phosphatase were similar in many respects, but different in some. Thus, the molecular weight of each was approximately 100,000. With p-nitro-phenyl phosphate as substrate, the Michaelis constant was 0.091 0.007 mM for the crystalline isoenzyme and 0.047 0.004 for the PII component. The isoelectric points of the crystalline and PII isoenzymes were pH 7.7 and 4.5, respectively, as determined by the method of isoelectric focusing. The activity of each isoenzyme was completely inhibited by 1 mM l-(-f)-tartrate or fluoride at a concentration of 1.0 mM" p-nitrophenyl phosphate as substrate. 

The corresponding rates for isoenzyme II were 50 and 66, and those for isoenzyme III were 7 and <2. The velocity of hydrolysis of other phosphate esters, such as glucose 6-phosphate or glucose 1-phosphate were, in general, low or negligible. An interesting property of isoenzyme III, not shared by either I or II, was the stimulation of its action on p-nitro-phenyl phosphate by various purines. For example, 5 mM adenine increased the activity by 83%, and 0.1 mM A -benzyladenine or iV -methyladenine by 35% and 34%, respectively. 6-Ethylmercaptopurine at a concentration of 1 mM had a stimulatory effect of 168%. 

Fio. 6. Effect of temperature on heat inactivation of proteinoid acting on p-nitro-phenyl phosphate. Aliquots of the nonbuffered proteinoid solutions were heated at the indicated temperatures for 6 minutes and were then assayed at 30°. Taken from Oshima (25). 

To date, four main types of catalytic activity have been reported in detail for thermal polyamino acids. These are (with the most studied substrates in parentheses) hydrolyses (p-nitrophenyl acetate, p-nitro-phenyl phosphate, ATP), decarboxylations (OAA, glucuronic acid, pyruvic acid), and aminations (a-ketoglutaric acid, OAA, pyruvic acid, phenylpyruvic acid). The fourth type is a deamination reaction yielding a-ketoglutaric acid (51). For some of the actions of the thermal polymers the products are identified quantitatively, and the kinds of amino acid side chain necessary for activity in the polymer elucidated. In others, products have yet to be fully identified. The activities of thermal polyamino acids are manifest on substrates which range from chemically labile to relatively stable. 

Commercial ISEs are made with liquid membranes involving both ion-exchanging systems and ionophores (see table 9.7). The solvent used is a hydrophobic liquid with a low relative permittivity. Examples include decane-l-ol, 5-phenyl pen tan-2-01, octyl phtalate, tri-n-phenyl phosphate, and 2-nitro-/ -cymene. Another important property of the solvent is that it have a low vapor pressure so that it is not... 

A zinc complex of the BPAN (2,7-bis[2-(2-pyridylethyl)aminomethyl]-l,8-naphthyridine ligand, [(BPAN)Zn2(p-0H)(p-Ph2P02)](C104)2, Fig. 27) catalyzes the transesterification of the RNA model substrate HPNP (2-hydroxypropyl 4-nitro-phenyl phosphate (Fig. 40, bottom) in aqueous buffered solution (HEPES) containing 1% CH3CN.141 The rate of this reaction was found to be 7 times fast than the reaction catalyzed by a mononuclear Zn(II) complex of bpta (Fig. 25). A pH-rate... 

The role of the APS sulfohydrolases in sulfate metabolism is not understood precisely. The lysosomal APS sulfohydrolase can hydrolyze bis(4-nitro-phenyl) phosphate and 4-nitrophenyl 5 -phosphothymidine (Roger et al., 1978). Thus the lysosomal APS sulfohydrolase is less specific than its cytosolic counterpart, which does not hydrolyze these nitrophenyl derivatives. The apparent role of the lysosomal enzyme is to hydrolyze the acid anhydrides of such compounds as FAD, ATP, and ADP in secondary lysosomes. Thus lysosomal APS sulfohydrolase is an acid anhydride hydrolase that helps the cell in the recovery of nucleoside monophosphates from acid anhydrides. The APS sulfohydrolase in the cytosolic fraction probably regulates the concentrations of PAPS and therefore plays an important role in the control of sulfate conjugation. 

Taguchi, Y. and Mushika, Y. (1975) 2-(N,N-Diethylamino)-4-nitro-phenyl phosphate and its use in the selective phosphorylation of unprotected nucleosides. Tetrahedron Lett. 24 1913-1916. 

Jones, D., Lindoy L.F. and Sargeson, A.M. (1983) Hydrolysis of phosphate esters bound to cobalt (III). Kinetics and mechanism of intramolecular attack of hydroxide on coordinated 4-nitro-phenyl phosphate. Journal of the American Chemical Society 1 05, 7327-7336. 

Zm complex (45) provided a model for the Zm -activated serine of AP (see Scheme 10). An alkoxide group in (45b) attacked BNPP to give a phosphorylserine intermediate (46), which was susceptible to further hydrolysis by the intramolecular Zn -bound hydroxide in (46b) to give (47) (Scheme 33). For the first step, the alcohol group is deprotonated by the proximate Zn (p7 a = 7.5) to an alkoxide complex (45b), which was 125 times more effective as nucleophile to the phosphate substrate than was the Zn -activated water of the reference compound (34). For the subsequent step, the nucleophilic Zn species (46c) was generated with a pXa value of 9. This intramolecular hydrolysis is 45,000 times faster than the intermolecular hydrolysis of ethyl 4-nitro-phenyl phosphate (ENP) with (34b). These results imply an advantage of the intramolecular arrangement of two Zn ions in AP (as shown in Scheme 10) over mononuclear Zn hydrolases. Toward any mononuclear Zn phosphatase model, phosphomonoesters were not substrates, but instead were inhibitors, as shown by isolation of the stable complexes (43), (44), and (47). The tris(pyrazolyl)-hydroborate complexes such as (35) and (38) hydrolyze phosphodiesters to phosphomonoesters, which similarly bind to Zn to become inert to further hydrolysis. ... 

In addition to the substances described, several other compounds have been described as lipase inhibitors. Thus pancreatic lipase is inhibited by thiourea, chloroethanol, formaldehyde (351), by quinine and atoxyl (352), by chaulmoogric acid (353), by cinnamate and ricinoleate (354), by several fatty acids (355), by vitamin C (356), by chlortetracycline (357), by isoamyl alcohol, isoamyl isobutyrate, and other esters (358), and by several sulfa drugs, such as sulfadiazine or sulfathiazole (340, 359, 360). Pancreatic lipase is unaffected by diisopropyl fluorophosphate (DFP) but is inhibited by diethyl-p-nitro-phenyl phosphate (349, 361). Milk lipase, however, is stated to be inhibited by DFP (362). 

A wide specificity for 2 -, 3 - and 5 -nucleotides also hydrolyses glycerol phosphate and 4-nitro-phenyl phosphate.]... 

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