Adenosine diphosphate metal complexes

ADP (Adenosine diphosphate) 536 in adenylate system 302 - 304 complexes with metal ions 296 dissociation as acid 288 intracellular concentration 304 P-31 NMR spectrum 642 pka value of 293 in regulation 535 ADP-ribose (ADPR) 315, 778, 780 ADP-ribosylation 545, 778 ADP-ribosylation factors (ARFs) 559 Adrenaline (epinephrine) 534, 542, 553, 553s in adrenergic receptor 535 a-Adrenergic receptors 553, 558, 563 p-Adrenergic receptors 553, 554 in asthma 553 in heart failure 553 receptor kinase 553 structure (proposed) 534, 555 topology 555... 

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... 

Ion-binding studies with biological molecules can be important in elucidating fundamental biochemical reaction systems in relation to bioenergetics, enzyme activation and membrane transport [182]. For example, the adenosine triphosphate (ATP)—adenosine diphosphate (ADP) cycle is one of the processes of primary importance to cellular energy systems and association constants determined [427—430] for metal—ATP and metal—ADP complexes are therefore of considerable interest Table 2.5). The constants may be obtained from measure-... 

Metal cofactors do not always bind to the enzyme but rather bind to the primary substrate. The resulting substrate-metal complex binds to the enzyme and facilitates its activity. Creatine kinase catalyses the transfer of phosphoryl groups from adenosine triphosphate (ATP), which is broken down to adenosine diphosphate (ADP). The reaction requires the presence of magnesium ions. These, however, do not bind to the enzyme but bind to ATP, forming an ATP Mg complex. It is this complex that binds to the enzyme and allows transfer of the phosphoryl group ... 

Adenosine-5 -triphosphate (ATP) forms bidentate A- and A- complexes of the type [Cr(H20)4(ATP)] [stmctures (1) and (2)]. Hydrolysis gives predominantly free ATP with very little of the diphosphate, ADP, being formed. The rate constant is 5 x 10"" s at 310 K and pH 11. The terdentate ATP complex [Cr(H20)3(ATP)] is also formed, and interestingly this hydrolyzes to give mostly ADP and very little free ATP (fc 5 x 10" s at pH 11 and 310 K). The rate constant is 5000 times as large as the value observed for the alkaline hydrolysis of ATP in the absence of metal ions. ... 

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