Diadenosine pentaphosphate

Triton X-100, EDTA, dithiothreitol and electrolyte protect enzyme in dilute solution and against denaturation by heat or extreme pH-values [12, 48] <2>, at low dithioerythritol concentrations enzyme tends to aggregate [5] <2>, bovine serum albumin, 1 mg/ml, stabilizes dilute enzyme solutions [5] <2>, diadenosine pentaphosphate, i.e. AP5A, stabilizes during preparative electrophoresis [7]... 

After these general comments let us further test the idea of thermodynamic buffering on an experimental basis by repeating the above experiment but this time in the presence of an inhibitor of adenylate kinase, namely, diadenosine pentaphosphate. As is depicted in Fig. 6b the buffering effect of the adenylate kinase is abolished by inhibiting this enzyme and it becomes now possible to drive the system beyond the state of optimal efficiency by increasing the hexokinase concentration in the medium. Note that it was not possible to measure points closer to level flow than the ones shown in the figure. This is due to technical reasons. At the lowest phosphate potentials the ATP/ADP ratios where of the order... 

Finally, it is noted that with a chromatographic system capable of separating ATP, ADP, and AMP and two monitors (to detect both radiolabeled and unlabeled compounds), the presence of an ATPase would be readily picked up, since such an activity would produce an excessive amount of unlabeled ADP with a corresponding reduction in the level of the unlabeled ATP. Of course, the availability of inhibitors of the myokinase such as Pl,P5-diadenosine pentaphosphate, makes it possible to test more directly the conclusion that the ADP formed is due to this activity, since as a result of its inhibition there would be an increase in the amount of AMP recovered and a proportional decline in the level of ATP. 

Reagent layer Buffer, pH 7.0 ADP, glycerol, peroxidase Magnesium acetate Diadenosine pentaphosphate Glycerol kinase Leuco dye Glycerophosphate oxidase... 

---