scholarly journals Determination of Effector Binding Affinities Using Photoacoustic Calorimetry

2018 ◽  
Vol 114 (3) ◽  
pp. 416a
Author(s):  
Jovany J. Betancourt ◽  
Jaroslava Miksovska
Author(s):  
Yasujiro Murata ◽  
Shih-Ching Chuang ◽  
Fumiyuki Tanabe ◽  
Michihisa Murata ◽  
Koichi Komatsu

We present our study on the recognition of hydrogen isotopes by an open-cage fullerene through determination of binding affinity of isotopes H 2 /HD/D 2 with the open-cage fullerene and comparison of their relative molecular sizes through kinetic-isotope-release experiments. We took advantage of isotope H 2 /D 2 exchange that generated an equilibrium mixture of H 2 /HD/D 2 in a stainless steel autoclave to conduct high-pressure hydrogen insertion into an open-cage fullerene. The equilibrium constants of three isotopes with the open-cage fullerene were determined at various pressures and temperatures. Our results show a higher equilibrium constant for HD into open-cage fullerene than the other two isotopomers, which is consistent with its dipolar nature. D 2 molecule generally binds stronger than H 2 because of its heavier mass; however, the affinity for H 2 becomes larger than D 2 at lower temperature, when size effect becomes dominant. We further investigated the kinetics of H 2 /HD/D 2 release from open-cage fullerene, proving their relative escaping rates. D 2 was found to be the smallest and H 2 the largest molecule. This notion has not only supported the observed inversion of relative binding affinities between H 2 and D 2 , but also demonstrated that comparison of size difference of single molecules through non-convalent kinetic-isotope effect was applicable.


Author(s):  
Mohammad A. Alnajjar ◽  
Werner M Nau ◽  
Andreas Hennig

The accurate determination of ultra-high binding affinities in supramolecular host-guest chemistry is a challenging endeavour because direct binding titrations are generally limited to affinities <106 M-1 due to sensitivity constraints...


2007 ◽  
Vol 28 (11) ◽  
pp. 1832-1838 ◽  
Author(s):  
Alexandra R. Stettler ◽  
Philipp Krattiger ◽  
Helma Wennemers ◽  
Maria A. Schwarz

1988 ◽  
Vol 251 (1) ◽  
pp. 141-145 ◽  
Author(s):  
A A Horner ◽  
M Kusche ◽  
U Lindahl ◽  
C B Peterson

Rat skin heparin proteoglycans vary markedly in the proportions of their constituent polysaccharide chains that have high binding affinity for antithrombin. As the proportion of such chains in a proteoglycan rises, their degree of affinity for antithrombin also increases [Horner (1987) Biochem. J. 244, 693-698]. The antithrombin-binding-site densities of such chains have now been determined, by measuring heparin-induced enhancement of the intrinsic fluorescence of antithrombin and by chemical analysis for the disaccharide sequence glucuronosyl-N-sulphoglucosaminyl (3,6-di-O-sulphate), which is unique to this site in heparin [Lindahl, Bäckström, Thunberg & Leder (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 6551-6555]. Antithrombin-binding-site density ranged from one to five sites per chain.


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