Aqueous adenosine triphosphate

During a search for high-energy phosphates, Ponnamperuma was able to synthesize adenosine triphosphate (ATP) from ADP, AMP or adenosine from ethyl metaphosphate in dilute aqueous solution under the influence of UV light. The role of the UV irradiation is unclear, as the phosphate itself is a high-energy species (Ponnamperuma et al., 1963). 

Vinyl alcohol copolymer gel is hydrophilic and has been developed for aqueous-phase size-exclusion liquid chromatography however, it is less polar than the polysaccharides. Its specificity permits the direct injection of a biological sample without deproteinization. For example, blood serum from a patient suffering from chronic nephritis has been injected directly as a measure of the degree of dialysis (Figure 3.17). Adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate in red blood cells have also been separated directly (Figure 3.18). Theophylline in blood serum has been... 

Similarly, specific catalysts called enzymes are important factors in determining what reactions occur at an appreciable rate in biological systems. For example, adenosine triphosphate is thermodynamically unstable in aqueous solution with respect to hydrolysis to adenosine diphosphate and inorganic phosphate. Yet this reaction proceeds very slowly in the absence of the specific enzyme adenosine triphosphatase. This combination of thermodynamic control of direction and enzyme control of rate makes possible the finely balanced system that is a hving cell. 

Biological chemistry takes place in the aqueous environment of the body of an animal or plant. Therefore, in spite of the fact that the molecules involved are largely organic in nature, the chemistry is essential acid-base chemistry and therefore a good candidate for the application of the bond valence model, as the example of adenosine triphosphate discussed in the previous section (Section 13.5.4) shows. This section illustrates a number of other ways in which the model has been used in biological systems. 

As an example of a set of chemical reactions in aqueous solution that are of biochemical interest, consider the hydrolysis of adenosine triphosphate to adenosine diphosphate and inorganic phosphate in the neighborhood of pH 7. The... 

M.W. Hosseini, J.M. Lehn, Supramolecular Catalysis of Adenosine-Triphosphate Synthesis in Aqueous-Solution Mediated by a Macrocyclic Polyamine and Divalent Metal-Cations , J. Chem. Soc., Chem. Commun., 451 (1991)... 

The application of LSR to amino-acids has received some attention. (451-456, 498) Such studies are an essential preliminary to the use of LSR for amino-acid sequence determination in simple peptides and proteins. The latter are discussed more comprehensively in Section G. A detailed study has been made (453) of the interaction of Eu(iii), Pr(iii), Gd(iii), and La(iii) with iV-acetyl-L-3-nitrotyrosine in order to characterize the nitrotyrosine residue as a potential specific lanthanide binding site in proteins. The parameters of the dipolar interaction indicate a significant contribution from non axially symmetric terms. The conformations of the nucleotides cyclic j8-adenosine 3, 5 -phosphate (3, 5 -AMP) (457, 458) and adenosine triphosphate (ATP) (459) have been deduced using LSR. In the former case the conformation of the ribose and phosphate groups is consistent with the solid state structure. A combination of lanthanide shift and relaxation reagents was used to deduce the most favoured family of conformations for ATP in aqueous solution. One of these conformations corresponds closely to one of the crystal structure forms. 

The magnitudes of entropies of activation have provided valuable information regarding the details of the interactions between enzymes and substrates. The process of muscular contraction involves an interaction between the muscle enzyme myosin and adenosine triphosphate (ATP). Myosin is an enzyme which catalyzes the hydrolysis of ATP, a process which we have seen (p. 246) to be more exergonic than is the case for many other phosphates, and this hydrolysis contributes energy for contraction. Because of its catalytic action, myosin is also referred to as adenosine triphosphatase (ATP-ase). When the activated complex is formed from ATP ase and its substrate ATP, the entropy of activation is about 41 cal K" mol under approximately normal physiological conditions. We saw on p. 400, on the basis of a very simple electrostatic theory of AS values for ionic reactions in aqueous solution, that there will be a positive contribution of about 10 cal mol for each unit of the product [ [ % ( The long myosin molecules bear a series of positive... 

The integrated N2-fixing reaction catalyzed by N2ase is represented in its simplest form in Figure 2(6). Reactants are (1) an electron donor, (2) adenosine triphosphate (ATP) and divalent cation (M ), and (3) an electron acceptor. Protons of the aqueous media as well as any one of six additional classes of reducible substrates can function in this capacity. Products are (1) oxidized electron donor, (2) adenosine diphosphate (ADP), inorganic phosphate (Pi), and (3) H2 and the reduced product characteristic of any added reducible substrates, e.g., NH3 from... 

In aqueous solution, adenosine triphosphate (ATP) is hydrolyzed to adenosine disphosphate (ADP) and inorganic phosphate in the presence of myosin ... 

The conformational change of spermidine upon interaction with adenosine triphosphate in aqueous solution has been studied by Maruyoshi et who successfully determined /hc and /hh couplings for a sper-... 

The porous interiors of silica nanoparhcles can also be used as reservoirs for storing biomolecules. Some silica nanoparhcles contain clear mesoporous structures inside their parhcles for example, thiol-modified TEOS-based mesoporous silica nanoparhcles have been demonstrated as a novel controUed-release delivery vehicle [113]. These mesoporous silica nanoparhcles were used as reservoirs to soak up aqueous soluhons of vancomydn and adenosine triphosphate. The... 

The coordinating properties of a zinc 2,2 -bipyridyl unit with adenosine 5 -triphosphate and cytidine 5 -triphosphate were studied in aqueous solution. The binding of zinc to both phosphate and ATP nitrogen donor was observed with the potential for displacement of the ATP nitrogen donor by hydroxide.426 The interaction of zinc with the phosphate groups in a platinum(II) bound 2 -deoxyguanosine 5 -monophosphate has been studied in aqueous solution, with little difference noted in the coordinating properties of the phosphate residue or backbone relative to the free nucleobase.427... 

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