@article {4029,
	title = {Acid-induced unfolding of cytochrome c at different methanol concentrations: Electrospray ionization mass spectrometry specifically monitors changes in the tertiary structure},
	journal = {Biochemistry},
	volume = {36},
	number = {40},
	year = {1997},
	note = {ISI Document Delivery No.: YA264Times Cited: 132Cited Reference Count: 51},
	month = {Oct},
	pages = {12296-12302},
	type = {Article},
	abstract = {The acid-induced denaturation of ferricytochrome c (cyt c) was examined in aqueous solutions containing different concentrations of methanol by electrospray ionization mass spectrometry (ESI MS) and optical spectroscopy. Circular dichroism, fluorescence, and absorption spectroscopy show that at a low concentration of methanol (3\%) a decrease in pH induces a cooperative unfolding transition at around pH 2.6 that is accompanied by a breakdown of the native secondary and tertiary structure of the protein. In 50\% methanol the breakdown of the tertiary structure occurs at around pH 4.0, whereas the alpha-helical content remains largely intact over the whole pH range studied. In ESI MS different protein conformations in solution are monitored by the different charge state distributions they generate during ESI. The ESI mass spectra recorded at near-neutral pH for both methanol concentrations are very similar and show a maximum at (cyt c + 8H(+))8(+). Despite the different conformations of the protein in solution, the acid-denatured states for the two methanol concentrations also show very similar mass spectra with a maximum at (cyt c + 17H(+))17(+). This indicates that the charge state distribution generated during EST is not sensitive to the differences in the secondary structure of the denatured protein. The observed transition from low to high charge states is due to the breakdown of the tertiary structure in both cases. These findings suggest that ESI MS might be a general method to selectively monitor changes in the tertiary structure of proteins.},
	keywords = {ALPHA-HELIX, BETA-LACTOGLOBULIN, CIRCULAR-DICHROISM, DENATURED, FERRICYTOCHROME-C, HEME, PARTIALLY FOLDED STATE, PROBING CONFORMATIONAL-CHANGES, PROTEIN, STATE, TRIFLUOROETHANOL},
	isbn = {0006-2960},
	url = {<Go to ISI>://A1997YA26400034},
	author = {Konermann, L. and Douglas, D. J.}
}
@article {4155,
	title = {Intermolecular interactions of lysozyme and small alcohols: A calorimetric investigation},
	journal = {Journal of Physical Chemistry B},
	volume = {101},
	number = {29},
	year = {1997},
	note = {ISI Document Delivery No.: XM058Times Cited: 23Cited Reference Count: 34},
	month = {Jul},
	pages = {5755-5758},
	type = {Article},
	abstract = {Isothermal titration calorimetry was used to measure transfer enthalpies of hen egg white lysozyme from water to aqueous solutions of methanol, ethanol, 1-propanol, glycerol, and 2,2,2-trifluoroethanol. Excess partial molar enthalpies of lysozyme at infinite dilution in the alcoholic solvents, H-infinity(L)E, were calculated, and the dependence of H-infinity(L)E on the concentration of the alcohol, was utilized to elucidate the enthalpy of alcohol-protein interactions. Results show that, at low alcohol concentrations, alcohol-protein interactions are unfavorable in terms of enthalpy (endothermic), while at higher concentrations they are favorable (exothermic). The change from endothermic to exothermic interactions happened sharply over a narrow alcohol concentration interval, and was found to occur concurrently with denaturation of the protein in some but not all cases. Comparison of the present results with previous investigations of simple binary and ternary aqueous solutions suggests that the change of sign of the interaction enthalpy is related to the water-water hydrogen bonding properties in the alcohol mixtures. It is argued that modifications by the alcohol of the percolated hydrogen bond network govern the enthalpy of alcohol-lysozyme interactions in the most water-rich samples. This suggests that occupancy by the alcohol of a binding site on the surface of the protein may not be necessary for the alcohol to affect the properties of the protein. At higher alcohol concentrations the observed interaction enthalpies are dominated by direct ({\textquoteright}{\textquoteright}intrinsic{\textquoteright}{\textquoteright}) effects of protein-alcohol interactions, which are exothermic.},
	keywords = {25-DEGREES-C, ENERGIES, GLOBULAR-PROTEINS, INDUCED REVERSIBLE DENATURATION, MIXTURES, MONOHYDRIC ALCOHOLS, STABILIZATION, THERMODYNAMIC INVESTIGATIONS, TRIFLUOROETHANOL, VAPOR-PRESSURES, WATER},
	isbn = {1089-5647},
	url = {<Go to ISI>://A1997XM05800021},
	author = {Westh, P. and Koga,Yoshikata}
}
