Adenosine polyphosphate

Pietrowska-Borek, M. et al., 4-Coumarate coenzyme A ligase has the catalytic capacity to synthesize and reuse various (di)adenosine polyphosphates. Plant Physiol, 131, 1401, 2003. 

Fig. 2. Prebiotic synthesis of adenosine polyphosphates, adenosine phosphoroimidates and the imidazolide of AMP.

An unexpected reaction, the synthesis of (di)adenosine polyphosphate by 4CL in the presence of cinnamic acids, was described by Pietrowska-Borek et al (2003). 

Reimann and Zubay found that 5 -AMP is selectively converted to adenosines -polyphosphate when a solution of nucleotides, trimetaphosphate and MgC is evaporated down. These are the same conditions under which 2 (3 )-AMP is converted to 2, 3 -cyclic AMP. 

In the molecules of adenosine polyphosphates, one of the phosphoric add residues is linked to the nucleoside by an ester bond but the phosphoric add residues among themselves are joined by an anhydride bond much less stable than the ester bond. As we shall see the hydrolysis of anhydride linkages playrs an important part in biochemical energetics on accormt of thdr strongly exergonic nature. 

Figure 12 Gradient separation of bases, nucleosides and nucleoside mono- and polyphosphates. Column 0.6 x 45 cm. Aminex A-14 (20 3 p) in the chloride form. Eluent 0.1 M 2-methyl-2-amino-l-propanol delivered in a gradient from pH 9.9-100 mM NaCl to pH 10.0-400 mM NaCl. Flow rate 100 ml/hr. Temperature 55°C. Detection UV at 254 nm. Abbreviations (Cyt) cytosine, (Cyd) cytidine, (Ado) adenosine, (Urd) uridine, (Thyd) thymidine, (Ura) uracil, (CMP) cytidine monophosphate, (Gua) guanine, (Guo) guanosine, (Xan) xanthine, (Hyp) hypoxanthine, (Ino) inosine, (Ade) adenosine, (UMP) uridine monophosphate, (CDP) cytidine diphosphate, (AMP) adenosine monophosphate, (GMP) guanosine monophosphate, (IMP) inosine monophosphate, (CTP) cytidine triphosphate, (ADP) adenosine diphosphate, (UDP) uridine monophosphate, (GDP) guanosine diphosphate, (UTP) uridine triphosphate, (ATP) adenosine triphosphate, (GTP), guanosine triphosphate. (Reproduced with permission of Elsevier Science from Floridi, A., Palmerini, C. A., and Fini, C., /. Chromatogr., 138, 203, 1977.)...

A nucleoside consists of a purine or pyrimidine base linked to a pentose, either D-ribose to form a ribonucleo-side or 2-deoxy-D-ribose to form a deoxyribonucleoside. Three major purine bases and their corresponding ribo-nucleosides are adenine/adenosine, guanine/guanosine and hypoxanthine/inosine. The three major pyrimidines and their corresponding ribonucleosides are cytosine/ cytodine, uracil/uradine and thymine/thymidine. A nucleotide such as ATP (Fig. 17-1) is a phosphate or polyphosphate ester of a nucleoside. 

AOPCP, a, P-methylene-adenosine diphosphate APnA, diadenosine polyphosphate (n=3-6) ARL 67156,6-N,N-diethyl-D- 3,y-dibromomethylene ATP CMTA, 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylic acid EHNA, erythro-9-(2-hydroxy-3-nonyl)adenine NBTI, nitrobenzylthioinosine. 

Because many cells maintain ATP, ADP, and AMP concentrations at or near the mass action ratio of the adenylate kinase reaction, the cellular content of this enzyme is often quite high. A consequence of such abundance is that, even after extensive purification, many proteins and enzymes contain traces of adenylate kinase activity. The presence of this kinase can confound the quantitative analysis of processes that either require ADP or are carried out in the presence of both ATP and AMP. Furthermore, the equilibrium of any reaction producing ADP may be altered if adenylate kinase activity is present. To minimize the effect of adenylate kinase, one can utilize the bisubstrate geometrical analogues Ap4A and ApsA to occupy simultaneously both substrate binding pockets of this kinase . Typical inhibitory concentrations are 0.4 and 0.2 mM, respectively. Of course, as is the case for the use of any inhibitor, one must always determine whether Ap4A or ApsA has a direct effect on a particular reaction under examination. For example. Powers et al studied the effect of a series of o ,co-di-(adenosine 5 )-polyphosphates (e.g., ApnA, where n =... 

Reactions involving the formation and hydrolysis of phosphate and polyphosphate esters are of vital importance in biological systems in which it is found that magnesium ions are almost invariably implicated. The formation and decomposition of adenosine triphosphate are the fundamental reactions involved in energy storage in living systems. In this context, it is perhaps relevant to note that the hydrolysis of ATP is enhanced, albeit in a very modest manner, by some cobalt(m) complexes. 

Condensed phosphates, other than branched phosphates, are stable in neutral aqueous solution at room temperature. The hydrolysis of the P-O-P bond in linear polyphosphates such as Graham s salt liberates energy equivalent to approximately 10 kcal/mol (Yoshida, 1955a,b Van Wazer, 1958), i.e. the same amount of energy as is liberated in the hydrolysis of the terminal phosphoric anhydride bonds in the adenosine 5 -triphosphate (ATP) molecule. Hydrolysis of the cyclotriphosphate also liberates this same amount of energy (Meyerhof etal, 1953). 

J. P. Ebel and G. Dirheimer (1957). Relations metaboliques entre polyphosphates inorganiques el adenosine di- et triphosphates. C. R. Soc. Biol., 151, 979-981. 

P. J. Horn, N. F. B. Phillips and H. G. Wood (1991). Photoinactivation of a polyphosphate/ATP dependent glucokinase by 8-azido-adenosine-5 -triphosphate. FASEB J., 5, A420. 

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