Adenosine triphosphate release from

Farinas 1, Solsona C, Marsal J. Omega-conotoxin differentially blocks acetylcholine and adenosine triphosphate releases from Torpedo synaptosomes. Neuroscience 1992 47(3) 641-8. 

Sprague, R. S., Ellsworth, M. L., Stephenson, A. H., Lonigro, A. J. Increases in flow rate stimulate adenosine triphosphate release from red blood cells in isolated rabbit lungs. Experimental Clinical Cardiology, 1998, 3, 73-77. 

Ill these simultaneous reactions, die energy released when the complex molecule AB is broken down is immediately used to build a molecule of adenosine triphosphate (ATP) from a molecule of adenosine diphosphate (ADP) and an inorganic phosphate (P,). ATP is a high energy compound. It is called the energy currency of the body because once it is formed, it provides energy that the body can spend later to drive vital reactions in cells (Figure 1). 

Figure 29.1 An overview of catabolic pathways for the degradation of food and the production of biochemical energy. The ultimate products of food catabolism are C02 and H2O, with the energy released in the citric acid cycle used to drive the endergonic synthesis of adenosine triphosphate (ATP) from adenosine diphosphate (ADP) plus phosphate ion, HOPO32-.

The energy released is used to transfer protons across the photosynthetic membrane and ultimately this energy acts as a driving force for the catalysed production of high-energy adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate. 

We may suppose that the photosynthetic organisms learned to recombine products of the photochemical oxidation-reduction reaction in a useful way. The energy released by this recombination was used to bring about the formation of the biological acid anhydrides, such as adenosine triphosphate (ATP) from inorganic phosphate, and organic phosphates such as adenosine diphosphate (ADP). 

The halophilic Archaea have a purple pigment that absorbs light by producing a transmembrane flow of protons from the interior towards the outside. The energy released by this transfer allows the synthesis of adenosine triphosphate (ATP) from ADP (adenosine diphosphate). This purple pigment, called bacteriorhodopsin, is known... 

Phosphate condensation reactions play an essential role in metabolism. Recall from Section 14.6 that the conversion of adenosine diphosphate (ADP) to adenosine triphosphate (ATP) requires an input of free energy ADP -I-H3 PO4 ATP +H2O AG° — +30.6kJ As also described in that section, ATP serves as a major biochemical energy source, releasing energy in the reverse, hydrolysis, reaction. The ease of interchanging O—H and O—P bonds probably accounts for the fact that nature chose a phosphate condensation/hydrolysis reaction for energy storage and transport. 

Note that equation 5.2 is irreversible and the product AMP will require two phosphorylation steps to reconstitute the high-energy adenosine triphosphate, ATP. Inositol 1,4,5-triphosphate is an important molecule in the cytosol, where it releases calcium ions from storage. It forms part of a series of inositol-phosphate species that mediate calcium ion concentrations inside and outside the cell. 

Nucleosides are also encountered in the structures of adenosine triphosphate (ATP) and coenzyme A (HSCoA). ATP provides nature with its currency unit for energy. Hydrolysis of ATP to adenosine diphosphate (ADP) liberates energy, which can be coupled to energy-requiring processes in biochemistry, and synthesis of ATP from ADP can be coupled to energy-releasing processes (see Box 7.25). 

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