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Counteraction ability of TMAO toward different denaturing agents
Author(s) -
Vigorita Marilisa,
Cozzolino Serena,
Oliva Rosario,
Graziano Giuseppe,
Del Vecchio Pompea
Publication year - 2018
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.23104
Subject(s) - chemistry , aqueous solution , tetramethylurea , trimethylamine n oxide , guanidinium chloride , urea , ternary operation , trimethylamine , formamide , differential scanning calorimetry , hydrogen bond , solvent , molecule , organic chemistry , thermodynamics , physics , computer science , programming language , enzyme
Differential scanning calorimetry measurements performed on RNase A in aqueous binary solutions containing different concentrations of urea, tetramethylurea, guanidinium chloride, and guanidinium thiocyanate, and in aqueous ternary solutions, containing the same denaturants plus 1 M trimethylamine N ‐oxide, TMAO, demonstrate that the latter has a general counteracting ability at pH 7.0, but not at pH 4.0. Experimental data rule out the idea that counteraction originates from direct interactions between TMAO molecules and denaturing agents. A rationalization is provided on the basis of a theoretical approach grounded on the solvent‐excluded volume effect, whose magnitude depends on the density of aqueous solutions.