Phosphorescence lifetime studies of interactions between serum albumins and sodium dodecyl sulfate.
Binding of sodium dodecyl sulfate (SDS) to bovine serum albumin (BSA) and human serum albumin (HSA) in aqueous solutions at room temperature induces significant changes in the phosphorescence lifetime of tryptophan (Trp) residues. A steep rise of the phosphorescence lifetime from 1.9 ms to 10.0 ms for BSA and from 1.9 ms to 5.5 ms for HSA is observed when the total SDS concentration increases from 0.0 mM to 0.22 mM at 1 mg/mL protein concentration. As the total SDS concentration is further increased to 2.2 mM, a slower increase in the phosphorescence lifetime is observed, from 10.0 ms to 19.5 ms for BSA and from 5.5 ms to 7.2 ms for HSA. It appears that the phosphorescence lifetime modifications are mainly due to an increase of protein matrix rigidity around Trp residues. The observed differences (between HSA and BSA) allow us to distinguish the contribution of the two Trp residues to the BSA phosphorescence.
Enescu
M
M
Institute of Atomic Physics, Lasers Department, Bucharest, Romania.
Ionescu
R
R
Dumbraveanu
G
G
Pascu
M L
ML
D006801:Humans; D049449:Luminescence; D012709:Serum Albumin / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000378:metabolism*; D013053:Spectrophotometry
D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D012967:Sodium Dodecyl Sulfate