Partially folded state of the disulfide-reduced form of human serum albumin as an intermediate for reversible denaturation.
The conformation of the fully disulfide-reduced state of human serum albumin was investigated by tryptophan fluorescence spectrum, CD analyses, and size-exclusion chromatography. Both the reduction of the native disulfide-bonded form under nondenaturing conditions and the refolding of the urea-denatured disulfide-reduced form under reduced conditions yielded almost exactly the same disulfide-reduced state with partially folded unique conformation that was clearly distinguished from either the native or fully denatured state. In addition, the interconversion between the urea-denatured reduced form and the partially folded reduced form was reversible with each other; by reoxidation, the partially folded reduced form was converted to the disulfide-bonded form. The conformation of disulfide-reduced serum albumin was highly variable depending on pH and ionic strength conditions. Thus, we concluded that the disulfide-reduced state with partially folded variable conformation is involved in the reversible interconversion between the denatured reduced form and the native disulfide-bonded form of human serum albumin.
Lee
J Y
JY
Research Institute for Food Science, Kyoto University, Japan.
Hirose
M
M
D002850:Chromatography, Gel; D002942:Circular Dichroism; D004220:Disulfides / Q000737:chemistry*; D005454:Fluorescence Polarization; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D011487:Protein Conformation; D011489:Protein Denaturation; D012709:Serum Albumin / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D014364:Tryptophan
D004220:Disulfides; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D014364:Tryptophan