Phosphoric acid esters phosphorylation

An enzyme that catalyzes the hydrolysis of phosphoric acid esters. phosphorylation ... 

If primary alcohols with a straight chain of 10-20 carbon atoms are initially alkoxylated by a mixture of ethylene and propylene oxides followed by phosphorylation, a pour point depression to 8°C will occur, whereas phosphate esters derived from nonylphenol are liquid at temperatures as low as 2°C. Phosphoric acid esters on the base of linear primary alcohols (Cn-Cl5) generally solidify below 24°C [50] (Table 2). 

Esters of N-phosphoryl phosphazenes are usually formed by the Staudinger reaction which requires the handling of the extremely toxic phosphoric acid ester azides (eq. 1). For developing new synthetic... 

The nucleotides are phosphoric acid esters of nucleosides, with phosphate at position C-5. Nucleotides with phosphorylation at other positions are known, but they are not components of the nucleic acids. Nucleotides containing deoxyribose are called deoxyribonucleotides those containing ribose are known as ribonucleotides. 

Phosphorylation is the process of introducing enzymatically a phosphoric acid residue into a protein from ATP as a phosphoryldonor. This results in the formation of a covalent phosphoric acid ester with the OH-groups of serine/threonine or with the phenolic group of tyrosine residues, or the formation of a phosphamide in N-phosphohistidine. 

OUgo)phosphoric acid esters, e.g., phosphorylated alcohols, sugars... 

Phospholipases are very versatile enzymes which allow the transformation of inexpensive natural products into highly valuable compounds like specific structurally defined phospholipids, organic monophosphates or diphosphates and DAG with the natural absolute configuration. Of particular synthetic utility is PLD from bacterial sources which is able to effect the phosphoryl transfer in a water-containing biphasic system. PLD shows a wide substrate specificity for both the polar head and the alcohol acceptors as well as for the lipophilic part of the molecule. The enzyme behaves like a generic phosphodiesterase with broad substrate specificity and high transphosphatidylation ability. The molecular basis of this behavior should become clear by inspection of the three-dimensional structure and comparison with other phosphoric acid ester hydrolytic enzymes. The crystal structure of this enzyme has not been elucidated. The potential of the many different PLD from plants which show peculiar substrate specificity should allow one to expand the synthetic utility to the hydrolysis-synthesis of natural and unnatural phosphatidylinositols. 

S.D. Alexandratos, M.A. Strand, D.R. Quillen and A.J. Walder, Synthesis and characteristics of bifunctional phosphinic acid resins, Macromolecules, 1985, 18, 829 R.H. Selzer and D.G. Howery, Phosphoric acid ester cation-exchange resins. 1. Synthesis and preliminary characterization, Macromolecules, 1986, 19, 2673 Phos-phonic acid ester cation-exchange resins. 2. Physicochemical characterization, ibid., 1986, 19, 2974 Y. An, T. Koyama, K. Hanabusa, A. Yamada, H. Shirai, J. Ikeda and H. Yoneno, Preparation of cation exchanger based on cross-linked phosphorylated... 

Newly laid eggs of the locust Locusta migratoria contain as the major ecdy-steroid 22-(adenosine 5 -monophosphoryl)-2-deoxyecdysone (33). During embryonic development (33) is hydrolysed to the free deoxyecdysone which is subsequently metabolized to 3-dehydro-2-deoxyecdysone and 2-deoxy-3-epiecdysone. The latter accumulates at a late stage of development as the 3-phosphoric acid ester. The 22-phosphoric ester of 2-deoxyecdysone is also present during embryonic development but it is uncertain whether the latter arises from the hydrolysis of (33) or by de novo phosphorylation of the 2-de-oxyecdysone. 

Phosphorylation of microcrystalline cellulose under the action of microwave irradiation was achieved by Gospodinova et al. [83]. The reactions were performed in a single-mode microwave reactor under an argon atmosphere. Mixtures of 29.0 mmol urea, 17.6 mmol phosphorous acid, and 1.8 mmol cellulose were irradiated for 60 to 120 min at temperatures from 75 to 150 °C (Scheme 14.42). The process led to monosubstituted phosphorous acid esters of cellulose with different degrees of substitution of hydroxy functions (0.2 to 2.8) without pretreatment with solvents. 

Mg ions activate some enzymes which hydrolyze phosphoric acid ester bonds (e. g. phosphatases cf. Table 2.4) or transfer phosphate residues from ATP to a suitable acceptor (e. g. kinases cf. Table 2.4). In both cases, Mg ions act as an electrophilic Lewis acid, polarize the P—O-linkage of the phosphate residue of the substrate or cosubstrate and, thus, facilitate a nucleophilic attack (water with hydrolases ROH in the case of kinases). An example is the hexokinase enzyme (cf. Table 2.16) which, in glycolysis, is involved in catalyzing the phosphorylation of glucose to glucose-6-phosphate with ATP as cosubstrate. The effect of a Mg ion within the enzyme-substrate complex is obvious from the following formulation ... 

Phosphorous acid esters from phosphoryl phosphites ... 

Phosphorus. Eighty-five percent of the phosphoms, the second most abundant element in the human body, is located in bones and teeth (24,35). Whereas there is constant exchange of calcium and phosphoms between bones and blood, there is very Httle turnover in teeth (25). The Ca P ratio in bones is constant at about 2 1. Every tissue and cell contains phosphoms, generally as a salt or ester of mono-, di-, or tribasic phosphoric acid, as phosphoHpids, or as phosphorylated sugars (24). Phosphoms is involved in a large number and wide variety of metaboHc functions. Examples are carbohydrate metaboHsm (36,37), adenosine triphosphate (ATP) from fatty acid metaboHsm (38), and oxidative phosphorylation (36,39). Common food sources rich in phosphoms are Hsted in Table 5 (see also Phosphorus compounds). 

In order to obtain anionic polyoxyethylene phosphate surfactants, either the terminal hydroxy group of a polyoxyethylated hydrophobic substance is reacted with a phosphorylating agent or a phosphate ester is oxalkylated. Most often aliphatic and aliphatic-aromatic alcohols are first treated with an alkylene oxide and afterward with one of the phosphorylating agents, such as P4OI0, POCl3, phosphoric acid, or polyphosphoric acid [39-48]. 

The development of monoalkyl phosphate as a low skin irritating anionic surfactant is accented in a review with 30 references on monoalkyl phosphate salts, including surface-active properties, cutaneous effects, and applications to paste and liquid-type skin cleansers, and also phosphorylation reactions from the viewpoint of industrial production [26]. Amine salts of acrylate ester polymers, which are physiologically acceptable and useful as surfactants, are prepared by transesterification of alkyl acrylate polymers with 4-morpholinethanol or the alkanolamines and fatty alcohols or alkoxylated alkylphenols, and neutralizing with carboxylic or phosphoric acid. The polymer salt was used as an emulsifying agent for oils and waxes [70]. Preparation of pharmaceutical liposomes with surfactants derived from phosphoric acid is described in [279]. Lipid bilayer vesicles comprise an anionic or zwitterionic surfactant which when dispersed in H20 at a temperature above the phase transition temperature is in a micellar phase and a second lipid which is a single-chain fatty acid, fatty acid ester, or fatty alcohol which is in an emulsion phase, and cholesterol or a derivative. 

A. Synthetic Methods.—There have been no strikingly new approaches to the general problem of phosphorylation, but several ingenious methods of preparing suitable active esters under mild conditions have been reported. Typical of these is the reactive intermediate (1) formed from reaction of a mono- or di-ester of phosphoric acid with (2), itself produced by reaction of triphenylphosphine with bis(2-pyridyl) disulphide (preferably in the presence of mercuric ion as scavenger for the 2-mercaptopyridine liberated). 

As will be shown below in subsequent chapters, CDI reacts in a corresponding way with sulfonic acids, which lead via the corresponding imidazolides to sulfonamides or sulfonic esters, and with phosphoric acid, which reacts with CDI to give the corresponding imidazolides of phosphoric acids that can in turn be used for phosphorylations. 

The monomeric metaphosphate ion itself commands a fair amount of attention in discussions of metaphosphates. It is postulated as an intermediate of numerous hydrolysis reactions of phosphoric esters 52 S4,S5) and also of phosphorylation reactions S6> kinetic and mechanistic studies demonstrate the plausibility of such an assumption. In addition, the transient formation of ester derivatives of meta-phosphoric acid — in which the double-bonded oxygen can also be replaced by thio and imino — has also been observed they were detected mainly on the basis of the electrophilic nature of the phosphorus. 

A further important group of derivatives is that of amino acids activated by phosphoric acid or its esters. In nature, phosphorylation processes play an important activating role in peptide and protein synthesis. 

Accordingly, phosphoric acid mono- and di-esters permit uncatalyzed glycosyl transfer from 0-(glycosyl)trichloroacetimidates (52a,55-57,58a,58b). The reaction is thus very useful in the synthesis of glycophos-pholipids (1,55), which are important constituents of cell membranes (1). Commonly, direct phosphorylation at the anomeric hydroxyl group leads to... 

Nakagome and co-workers effected the successful cyclization of N-ethyl-N-arylaminomethylenemalonates (749) in poly phosphoric acid, prepared from orthophosphoric acid and phosphorus pentoxide in polyphosphate ester (PPE), prepared from phosphorus pentoxide and anhydrous diethyl ether in chloroform in phosphoryl chloride on the action of boron trifluoride etherate on the action of acetic anhydride and concentrated sulfuric acid or on the action of phosphorus pentoxide in benzene [71GEP2033971, 71JHC357 76JAP(K) 18440]. Depending on the work-up process, l-ethyl-4-oxoquinoline-3-carboxylates (750, R1 = Et), l-ethyl-4-oxoquinoline-3-carboxylic acids (750, R2 = H) and 3-ethoxycarbonyl-4-chloroquinolinium iodides (751) were obtained. Only the cyclization of... 

These compounds contain the fragment R as an alkyl or aryl moiety. In other words, they result from the esterification of an alcohol or a phenol with nitrous acid, nitric acid, phosphoric acid, sulfuric acid, or sulfamic acid, respectively. Many of the esters to be examined in this chapter must be activated prior to eliciting their effects, e.g., the organic nitrites and nitrates, which act as donors of nitric oxide or an analogous molecule, and phosphates, which are activated by hydrolysis or even by phosphorylation (antiviral agents). Sulfates are very seldom active or used as prodrugs, but they have significance as metabolites and as industrial xenobiotics. 

The subsequent cleavage of the thio-ester succinylCoA into succinate and coenzyme A by succinic acid-CoA ligase (succinyl CoA synthetase, succinic thiokinase) is strongly exergonic and is used to synthesize a phosphoric acid anhydride bond ( substrate level phosphorylation , see p. 124). However, it is not ATP that is produced here as is otherwise usually the case, but instead guanosine triphosphate (CTP). However, GTP can be converted into ATP by a nucleoside diphosphate kinase (not shown). 

The ester of the phosphorous acid or organophos-phorsus inhibitors of the acetylcholine esterase phos-phorylate serine in the active center of the enzyme. The phosphorylated enzyme is extremely stable, resulting in an irreversible inhibition. The duration of action of this compounds is determined by the rate of enzyme synthesis de novo. 

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