Adenosine triphosphate biochemical reactions

Adenosine triphosphate (ATP) Common energy-donating molecule in biochemical reactions. Also an important compound in transfer of phosphate groups. 

McElroy, W. D., and Strehler, B. L. (1949). Factors influencing the response of the bioluminescent reaction to adenosine triphosphate. Arch. Biochem. 22 420-433. 

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. 

Magnesium is the second most abundant intracellular cation. Magnesium serves as an essential cofactor for numerous enzymes and in many biochemical reactions, including reactions involving adenosine triphosphate (ATP).17 Magnesium disorders can be multifactorial and can be related to renal function, disease... 

For many biochemical reaction, such as the hydrolysis of adenosine triphosphate,... 

ATP, adenosine triphosphate, provides the currency unit for energy in biochemical reactions (see Section 15.1.1) and is simply a triphosphate variant of a standard RNA nucleotide. It is, of course, the biosynthetic precursor for adenine-based units in RNA (see Section 14.2.5). As we have already seen (see Box 7.25), the functions of ATP can be related to hydrolytic reactions in the triphosphate (anhydride) part of the molecule. 

Biochemical reactions frequently require energy. The most common source of chemical energy used is adenosine triphosphate (ATP). The splitting of a phosphate from the ATP molecule can provide the energy needed to make an otherwise unfavorable reaction proceed in the desired direction. 

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... 

In addition to their role in the formation of DNA and RNA (see Section 27.2), nucleotides have other important biological functions. For example, adenosine triphosphate (ATP) is an important energy carrier in biochemical reactions, and nicotinamide adenine dinucleotide is a coenzyme that is often involved in biochemical oxidation-reduction reactions. 

Chapters 3-5 have described the calculation of various transformed thermodynamic properties of biochemical reactants and reactions from standard thermodynamic properties of species, but they have not discussed how these species properties were determined. Of course, some species properties came directly out of the National Bureau of Standard Tables (1) and CODATA Tables (2). One way to calculate standard thermodynamic properties of species not in the tables of chemical thermodynamic properties is to express the apparent equilibrium constant K in terms of the equilibrium constant K of a reference chemical reaction, that is a reference reaction written in terms of species, and binding polynomials of reactants, as described in Chapter 2. In order to do this the piiTs of the reactants in the pH range of interest must be known, and if metal ions are bound, the dissociation constants of the metal ion complexes must also be known. For the hydrolysis of adenosine triphosphate to adenosine diphosphate, the apparent equilibrium constant is given by... 

The biochemical pathway of both assimilatory and dissimilatory sulfate reduction is illustrated in Figure 1. The details of the dissimilatory reduction pathway are useful for understanding the origin of bacterial stable isotopic fractionations. The overall pathways require the transfer of eight electrons, and proceed through a number of intermediate steps. The reduction of sulfate requires activation by ATP (adenosine triphosphate) to form adenosine phosphosulfate (APS). The enzyme ATP sulfurylase catalyzes this reaction. In dissimilatory reduction, the sulfate moiety of APS is reduced to sulfite (SO3 ) by the enzyme APS reductase, whereas in assimilatory reduction APS is further phosphorylated to phospho-adenosine phosphosulfate (PAPS) before reduction to the oxidation state of sulfite and sulfide. Although the reduction reactions occur in the cell s cytoplasm (i.e., the sulfate enters the cell), the electron transport chain for dissimilatory sulfate reduction occurs in proteins that are peiiplasmic (within the bacterial cell wall). The enzyme hydrogenase... 

The associated free energy produced or consumed in each reaction is captured in units of adenosine triphosphate (ATP). The ATP stoichiometry is usually obtained from biochemical tables since the energy has to be also balanced for the cell. Thus for Eq. (7-148) the stoichiometric ATP requirement to convert one C-mole of glucose to one C-mole of glycerol is 5. In calculations of the carbon flux distribution in different pathways this ATP requirement has to be added on the left-hand side of the equation. Again the other form of the cofactor ATP is usually left out to simplify the reaction equation. 

More complicated structures that form with longer chains or rings also exist. The biochemically most important polyphosphate is adenosine triphosphate, ATP, which contains three phosphorus tetrahedral units linked by -O-P-0- bonds. The hydrolysis of ATP to adenosine diphosphate, ADP, by the rupture of an 0-P bond releases energy that is used by cells to drive biochemical reactions within the cell. ATP + H2O ADP + HP04 " A//= - 41 kJ... 

Phosphorus is one of the most important elements on the Earth. It participates in or controls many of the biogeochemical processes occurring in the biosphere. The important role of phosphorus in the biosphere is owed to its vital role in protein synthesis. The exothermal reaction of adenosine triphosphate with photosynthesized hydrocarbons provides the subsequent biochemical reactions with energy (see structure and functions of DNA and RNA in Chapter 2, Box 5). The N P ratio in plant issues is within 8-15 (Bazilevich, 1974 Romankevich, 1982, Vitoushek and Howarth, 1991). Almost in all biogeochemical systems P was found as a deficient element limiting the productivity of ecosystems. 

In brief, enzymes are proteinaceous substances that catalyze biochemical reactions, and kinases constimte a subclass of the enzymes classified as transferases, which transfer functional groups. In turn, a kinase can be described as a phosphoryl-transfer enzyme utilizing ATP (adenosine triphosphate) or described as transferring a phosphate group from a nucleoside triphosphate to another molecule, according to the Academic Press Dictionary of Science and Technology. (Examples of some kinases and their actions occur in Figure 3.1 therein.)... 

This is the first reaction in the biochemical pathway called glycolysis. A phosphoryl group is transferred from a donor molecule, adenosine triphosphate, to the recipient molecule, glucose. The products are glucose-6-phosphate and adenosine diphosphate. This enz)rme, called hexokinase, is an example of a transferase. 

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