Thermodynamics of a molten globule state of human serum albumin by 3-β-hydroxybutyrate as a ketone body.

The molten globule (MG) state is an intermediate which is considered as the third thermodynamic state of protein molecules. In this work the effect of incubating human serum albumin (HSA) at physiological condition in the presence of 3-β-hydroxybutyrate for 7, 14, 21 and 35 days were studied by different techniques such as UV/vis, fluorescence and circular dichroism (CD) spectroscopy, differential scanning calorimetry (DSC) and dynamic light scattering (DLS). In this paper, we introduce the MG state for HSA upon 21 days incubation with 3-β-hydroxybutyrate as a ketone body at physiological condition. The results from the HSA sample incubated for 21 days shows a similar secondary structure by CD, more surface hydrophobicity and a little change on tertiary structure by fluorescence, and a larger size by DLS as compared to the native sample or other incubated samples. These results were also confirmed by calculated parameters and DSC deconvoluted thermograms.