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Thermal stability of lipid‐depleted purple membranes at neutral and low pH values
Author(s) -
Taneva Stefka G.,
Koynova Rumiana,
Tenchov Boris
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00426-9
Subject(s) - membrane , differential scanning calorimetry , chemistry , cooperativity , thermal stability , chromatography , analytical chemistry (journal) , biophysics , biochemistry , thermodynamics , organic chemistry , biology , physics
Differential scanning calorimetry was used to compare the thermal behavior of native and delipidated purple membrane fragments at pH values corresponding to purple, blue and acid‐purple forms. At neutral pH, delipidation results in a 2.5‐ to 3‐times increase in the cooperativity of the denaturational transition, accompanied by a minor increase in its temperature. At pH values below 5 the delipidated membranes exhibit considerably higher thermal stability than the native membranes. The reversible predenaturational transition observed in the native state is not detectable upon delipidation. There is no strict correlation between color changes upon acidification and deionization of either native or delipidated purple membranes and their thermal stability.