Pyrophosphate, inorganic

ADP, ATP FAD, DPN, TPN Thiamine pyrophosphate Inorganic pyrophosphate II. Low-Energy Phosphate Esters... 

PEROXIDES AND PEROXIDE COMPOUNDS - INORGANIC PEROXIDES] (Vol 18) Tetrapotassium pyrophosphate [7320-34-5]... 

Hg ", Zn ", Cd " ) light emission is shifted to the red (610—615 nm). In vitro a flash of light is produced (< 1 s) that decays rapidly. Glow-type emission is obtained ia the presence of detergents (Triton X-100), polymers (PEG 6000), coen2yme A, inorganic pyrophosphate, and cytidine nucleotides (206,207). 

There are occasions where the mud pH must be lowered such as after drilling fresh cement or overtreatment by one of the alkaline materials discussed. Organic acids that have been used for this purpose include acetic acid [64-19-7], citric acid [77-92-9], and oxaHc acid [144-62-7]. These materials are used infrequently. Inorganic additives used to lower pH levels include sodium bicarbonate [144-55-8] and sodium acid pyrophosphate [7758-16-9] (SAPP). Of the two, sodium bicarbonate is used the most by far. 

Of the large volume of tin compounds reported in the Hterature, possibly only ca 100 are commercially important. The most commercially significant inorganic compounds include stannic chloride, stannic oxide, potassium staimate, sodium staimate, staimous chloride, stannous fluoride, stannous fluoroborate, stannous oxide, stannous pyrophosphate, stannous sulfate, stannous 2-ethyUiexanoate, and stannous oxalate. Also important are organotins of the dimethyl tin, dibutyltin, tributyltin, dioctyltin, triphenyl tin, and tricyclohexyltin families. 

Other studies of the toxicity of stannous fluoride, sodium pentafluorostannite, sodium pentachlorostannite, sodium chlorostannate, stannous sulfide [1314-95-0] stannous and stannic oxides, stannous pyrophosphate [15578-26 ] stannous tartrate [815-85-0] and other inorganic tin compounds are reviewed in References (dh—12. The OSHA TLV standard for inorganic tin compounds is two milligrams of inorganic tin compounds as tin per cubic meter of air averaged over an eight-hour work shift (47). 

The concepts of destabilization of reactants and stabilization of products described for pyrophosphate also apply for ATP and other phosphoric anhydrides (Figure 3.11). ATP and ADP are destabilized relative to the hydrolysis products by electrostatic repulsion, competing resonance, and entropy. AMP, on the other hand, is a phosphate ester (not an anhydride) possessing only a single phosphoryl group and is not markedly different from the product inorganic phosphate in terms of electrostatic repulsion and resonance stabilization. Thus, the AG° for hydrolysis of AMP is much smaller than the corresponding values for ATP and ADP. 

FIGURE 15.20 The adenylyl cyclase reaction yields 3, 5 -cyclic AMP and pyrophosphate. The reaction is driven forward by subsequent hydrolysis of pyrophosphate by the enzyme inorganic pyrophosphatase. 

Internal stress of copper deposits may vary between —3.4MN/m (compressive) and -1- l(X)MN/m (tensile). In general, tensile stress is considerably lower in deposits from the sulphate bath than in those from cyanide solutions " , while pyrophosphate copper deposits give intermediate values. In cyanide solutions, tensile stress increases with metal concentration and temperature decreases if the free cyanide concentration is raised. P.r. current significantly lowers tensile stress. With some exceptions, inorganic impurities tend to increase tensile stress . Thiocyanate may produce compressive stress in cyanide baths . 

Isopentenyl diphosphate is isomerized by a shift of the double bond to form dimethylallyl diphosphate, then condensed with another molecule of isopentenyl diphosphate to form the ten-carbon intermediate ger-anyl diphosphate (Figure 26-2). A further condensation with isopentenyl diphosphate forms farnesyl diphosphate. Two molecules of farnesyl diphosphate condense at the diphosphate end to form squalene. Initially, inorganic pyrophosphate is eliminated, forming presqualene diphosphate, which is then reduced by NADPH with elimination of a further inorganic pyrophosphate molecule. 

Both inorganic acids, such as hydrochloric acid and hydrofluoric acid, and organic acids, such as formic acid, can be used to increase the pH. Acids are used in combination with surfactants. Various phosphates, pyrophosphates. 

Nucleoside triphosphates are prepared analogously to the diphosphates by the methods a, b, c, and d, representing conversion of a nucleoside phosphoric azolide with inorganic pyrophosphate (Method a), of a nucleoside diphosphoric azolide with inorganic phosphate (Method b), of a phosphoric bisazolide with a nucleoside diphosphate (Method c), and of a diphosphoric bisazolide (bisazolide of pyrophosphoric acid) with a nucleoside phosphate (Method d). 

Whereas imidazolides of nucleotides react only in organic solvents with phosphates or pyrophosphates to give the corresponding anhydride derivatives in high yield, ATP can also be formed enzymatically in aqueous solution from AMP-Im with inorganic pyrophosphate in the presence of valyl-f-RNA synthetase.[66] A variant of this method is the one-pot reaction of a nucleoside with phosphoryltristriazole and tributylammonium pyrophosphate. 671 An a-methylphosphonyl-/ ,y-diphosphate of a thymidine derivative has been synthesized in a similar way t681... 

A mechanism proposed 87) for the alkaline hydrolysis of tetraethyl pyrophosphate, which is markedly accelerated by HPO e ions, has been substantiated by isotopic labeling 88). The nucleophilic attack by HPOJp on the symmetrical pyrophosphate 131 is considered to lead initially to the unsymmetrical P P1-diethyl pyrophosphate dianion 132 which decomposes spontaneously under the conditions of reaction to give the diethyl phosphate anion and POf 102. The latter reacts with water to form inorganic phosphate and with alcohols suclj as methanol and ethylene glycol to produce alkyl phosphates. 

Another way in which energy can be stored in aqueous solution is not only in organic compounds, as we shall see, but also in kinetically stable combinations of inorganic ions. An example is the molecule pyrophosphate, which stores energy at... 

Creatinine phosphate (CP + ADP —> creatinine + ATP) AMP Dissolved 02 Inorganic pyrophosphate Energy reservoir for muscle activity Mediator of hormone activity Measurement of water quality Medical Starting material for several biological compounds... 

A flow assay was reported for determination of inorganic pyrophosphate a pyrophosphatase was coimmobilized with luciferase on Sepharose beads with continuous flow of saturating concentrations of substrates. The instrument allowed automation with a throughput of approximately one sample every 4 min. 

FIGURE 21-2 Chemical pathways for the synthesis and degradation of cAMP. cAMP is synthesized from ATP by the enzyme adenylyl cyclase with the release of pyrophosphate, and is hydrolyzed into 5 -AMP by the enzyme phosphodiesterase. Both reactions require Mg2. Analogous reactions underlie the synthesis and degradation of cGMP (not shown). PP, inorganic pyrophosphate. 

These transport systems use a primary source of energy to drive active transport of a solute against a concentration gradient. Primary energy sources can be chemical, electrical and solar. In this section, systems will be described mainly that hydrolyse the diphosphate bond of inorganic pyrophosphate, ATP, or another nucleoside triphosphate, in order to drive the active uptake of solutes. Transporters using another primary source of energy will be briefly mentioned. 

---