Similar affinities of ADP and ATP for G‐actin at physiological salt concentrations

[摘要]

The equilibrium constant for the exchange of ATP and ADP at G-actin was determined by fluorimetric titration of G-actin-bound ε-ATP by ATP or ADP. The affinity of ATP for G-actin was found to be only about 3-fold higher than the affinity of ADP for G-actin at 37°C, pH 7.5 and physiologically relevant salt concentrations (100 mmol K⁺/l, 0.8 mmol Mg²⁺/l, <0.01 mmol Ca²⁺/l).

[学科分类] 生物化学/生物物理

[关键词] Actin;1-N6-Ethenoadenosine 5′-triphosphate;Fluorescence;Nucleotide exchange;Equilibrium constant;ATP;adenosine 5'-triphosphate;ADP;adenosine 5'-diphosphate;ε-ATP;1-N 6-ethenoadenosine 5'-triphosphate;NEM;N-ethylmaleimide;PEI;polyethylenimine;Tris;tris (hydroxymethyl)-aminomethane;EGTA;ethyleneglycol-bis-(β-aminoethyl ether)-N;N;N';N'-tetraacetic acid