Abstract:

Objective: To study the interaction between adenosine 5’-monophosphate (AMP) and actomyosin by
fluorophotometry. Methods: Based on the correlation between intermolecular interaction and related thermodynamic
parameters, as well as enthalpy change (ΔH) and entropy change (ΔS) for their interaction, the fluorescence quenching
mechanism of actomyosin by AMP was discussed. Quenching constant, binding equilibrium constant and the number of
binding sites were determined. The effect of AMP on the conformation of actomysin was also analyzed using synchronous
fluorescence spectrometry. Results: Western blotting demonstrated the promotion effect of different concentrations of AMP on
the dissociation of actomyosin; the combination between them were mainly via hydrophobic interaction, since ΔG < 0, ΔH > 0,
ΔS > 0 were found in the binding reaction of AMP and actomyosin, and the presence of AMP changes the conformation of
actomyosin, reduce the polar of hydrophobic environment; Fluorescence spectroscopy showed that the combination of AMP and
actomyosin makes the regular quenching of intrinsic fluorescence of actomyosin. At 298 K and 313 K, the KSV of combination
were 8.70 × 102 and 4.07 × 102 L/mol, KLB were 9.253 × 102 L/mol and 3.142 × 102 L/mol respectively. Conclusion: Different
concentrations of AMP can promote the dissociation of actinmyosin as demonstrated by Western blotting.

Key words: actomyosin, adenosine 5’-monophosphate, fluoresence quenching, dissociation