Association constant of Mg and ATP

Value 12 mM^-1
Organism Generic
Reference Berger H, Jänig GR, Gerber G, Ruckpaul K, Rapoport SM.(1973). Interaction of haemoglobin with ions. Interactions among magnesium, adenosine 5'-triphosphate, 2,3-bisphosphoglycerate, and oxygenated and deoxygenated human haemoglobin under simulated intracellular conditions. European Journal Of Biochemistry 38(3): 553-562. p. 557 left column top sentence and p. 559 table 4PubMed ID4772673
Method Researchers chose the data from (Phillips et al., 1966 PMID 5941264) to calculate the association constants prevailing under physiological conditions (ionic strength 0.15, 37°C). The Kass for the Mg2+ complexes of ATP4- and ATPH3- (MgATP2-, MgATPH1-) are 42.7 and 0.724mM^-1, respectively. The pK values for ATPH3- and MgATPH1- are 6.95 and 5.18, respectively. From these constants and those for NaATP and KATP (Kass˜13M^-1) [refs 25-27 in article] the K'ass was calculated to be 12mM^-1, which is in accordance with electrode measurements [table 2, p. 556 left column].
Entered by Ben Marks
ID 101768