Stability of proteins in the presence of polyols estimated from their guanidinium chloride-induced transition curves at different pH values and 25 °C

Stabilizing effect of polyols is sensitive to inherent stability of protein

“…Kaushik and Bhat [23] noticed that trehalose brought about a larger increment in the melting temperature of RNaseA at pH 2.5 than at pH 7.0, although they attributed this behavior to increased hydrophobicity of the protein molecule at pH 2.5 due to protonation of acidic groups rather than high prior stability of protein at pH 7.0 than at pH 2.5. Similar behavior was noticed by Haque et al [14,24] while working with lysozyme and RNase A at neutral and acidic pH. In contrast to previous studies which are limited to few pH values, our work on large number of lipase variants, created by directed evolution and wide pH range (3.3-12.1) helped us to establish an inverse linear relationship between increments in protein stability by polyol and prior stability of protein.…”

A current perspective on the compensatory effects of urea and methylamine on protein stability and function

“…Two essential characteristics of these osmolytes are that most stabilize proteins against denaturing stresses (Anjum et al, 2000;Cho et al, 2011;Foord and Leatherbarrow, 1998;Haque et al, 2006;Haque et al, 2005a;Haque et al, 2005b;Jamal et al, 2009;Kaushik and Bhat, 1998;Kim et al, 2003;Poddar et al, 2008;Santoro et al, 1992;Taneja and Ahmad, 1994;Welch and Brown, 1996;Xie and Timasheff, 1997a;Xie and Timasheff, 1997b), facilitate protein assemblies (Lampel et al, 2013;Silvers and Myers, 2013); and their presence in the cell does not largely alter protein functional activity (Myers and Jakoby, 1975;Wang and Bolen, 1996;Yancey et al, 1982). The natural selection of protecting osmolytes is based upon selection of a particular molecular-level that confers generic stabilization to all proteins and thus reduced genetic alteration (Yancey, 2003a;Yancey, 2004).…”

Thermodynamic analysis of sol–gel transition of gelatin in terms of water activity in various solutions

“… where m is an empirical parameter called as “ m ‐value,” which is positive for a protein stabilizer and negative for a denaturant. Because of the simplicity and easiness to use, LEM model has been applied to analyze the effect of electrolytes on denaturation of ribonuclease, unfolding of peptide helices by urea and guanidine HCl, urea‐induced unfolding of nuclease and its variants, RNA folding, and urea‐ and guanidine‐induced unfolding of ribonuclease and lysozyme although the complete linearity in Eq. is not necessarily guaranteed …”