Inclusion kinetics of a nucleotide into a cyclodextrin cavity by means of ultrasonic relaxation.
To examine a dynamic interaction between nucleotide and cyclic oligosaccharide, ultrasonic absorption measurements were carried out in aqueous solution containing beta-cyclodextrin (beta-CD) and adenosine 5'-monophosphate (AMP) in the frequency range of 0.8-95 MHz. A relaxational absorption was observed in the solution, although it was not found in the individual solution of beta-CD or AMP. From the concentration dependences of AMP on the relaxation time and the maximum absorption per wavelength, the cause of the relaxation was attributed to a perturbation of a chemical equilibrium associated with a complex formation between beta-CD (host) and AMP (guest). The rate constants for the formation and breakup processes of the complex were determined. Also, a standard volume change of the reaction was obtained. From comparisons of the obtained rate and thermodynamic parameters with those for beta-CD and various guests, it has been concluded that the adenine moiety is included in the beta-CD cavity and that the hydrogen bonds may play a role in the complex formation.
Kondo
Minako
M
Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, Saga, Japan 840-8502.
Nishikawa
Sadakatsu
S
D000225:Adenine / Q000737:chemistry; D000249:Adenosine Monophosphate / Q000737:chemistry; D006147:Guanine / Q000737:chemistry; D007700:Kinetics; D009711:Nucleotides / Q000737:chemistry*; D012996:Solutions; D013057:Spectrum Analysis; D013816:Thermodynamics; D014465:Ultrasonics; D047392:beta-Cyclodextrins / Q000737:chemistry*
D009711:Nucleotides; D012996:Solutions; D047392:beta-Cyclodextrins; D000249:Adenosine Monophosphate; D006147:Guanine; D000225:Adenine