Elucidating the mode of action of urea on mammalian serum albumins and protective effect of sodium dodecyl sulfate.
The effect of sodium dodecyl sulfate (SDS) on human, bovine, porcine, rabbit and sheep serum albumins were investigated at pH 3.5 by using various spectroscopic techniques like circular dichroism (CD), intrinsic fluorescence and dynamic light scattering (DLS). In the presence of 4.0mM SDS the secondary structure of all the albumins were not affected as measured by CD but fluorescence spectra revealed 8.0 nm blue shift in emission maxima. We further checked the stability of albumins in the absence and presence of 4.0mM SDS by urea and temperature at pH 3.5. In the absence of SDS, urea starts unfolding both secondary as well as tertiary structural elements of the all the albumins at approximately 2.0M urea but in the presence of 4.0mM SDS, urea was unable to unfold even up to 9.0M. The albumins were thermally less stable at pH 3.5 with decrease in Tm but in the presence of 4.0mM SDS, the Tm was increased. From this study, it was concluded that SDS is showing a protective effect against urea as well as thermal denaturation of albumins. This behavior may be due to electrostatic as well as the hydrophobic interaction of SDS with albumins. Further, we have proposed the mechanism of action of urea. It was found that urea interacted with proteins directly when proteins are in charged form. Indirect interaction may be taking place when the environment is more hydrophobic.
['Khan|Javed Masood|JM|', 'Chaturvedi|Sumit Kumar|SK|', 'Khan|Rizwan Hasan|RH|']
D000818:Animals D002417:Cattle D002942:Circular Dichroism D006358:Hot Temperature D006801:Humans D006863:Hydrogen-Ion Concentration D008027:Light D011489:Protein Denaturation D055550:Protein Stability D017433:Protein Structure, Secondary D011817:Rabbits D012542:Scattering, Radiation D012709:Serum Albumin D012756:Sheep D012967:Sodium Dodecyl Sulfate D013050:Spectrometry, Fluorescence D013552:Swine D014508:Urea
Urea Serum albumins SDS pH Stability Stabilization and unfolding