TITLE:
Excess adsorption of biomolecules on soft surfaces: Adsorption of DNA, proteins and lactose on fatty surfaces
AUTHORS:
Dipta Shani Dutta, Dipti Kumar Chattoraj, Parimal Chattopadhyay, Kali P. Das
KEYWORDS:
Excess Adsorption; Surface Adsorption of Biomolecules; Soft Surfaces; Adsorption on Soft Surfaces, DNA, Globular Proteins
JOURNAL NAME:
Advances in Biological Chemistry,
Vol.3 No.1,
February
22,
2013
ABSTRACT: Insoluble fatty surfaces are involved in many important interactions such as in biomembranes with soluble biological macro and
micromolecules. In this paper we have studied the adsorption interaction of
aqueous solution of DNA, some proteins and lactose on several sparingly soluble
fatty substances namely milk fat, stearic acid, palmitic acid, phosphatidyl choline and cholesterol surfaces by measuring the depletion of the adsorbates by
analytical methods. Adsorption () of DNA on the soft surfaces of
stearic acid, milk fat, phosphatidyl choline, palmitic acid and cholesterol
was measured as a function of DNA concentration C2. In each case was found to increase with C2 until
it reached the maximum value at a critical concentration . For different surfaces stands
in the order: stearic acid > milk fat > phosphatidyl choline >
cholesterol > palmitic acid. DNA forms multilayers on stearic acid surface.
Adsorption of hemoglobin on cholesterol surface is found to be negative or zero
but that of BSA on cholesterol is positive. Adsorption of gelatin on cholesterol
surface is significantly higher than that of BSA. Lysozyme on cholesterol
surface forms multilayers and on casein forms bilayer. The lowering of free energies
?DGo for all systems have been calculated using integrated form of the Gibbs
adsorption and their values have been compared with each other. It is concluded
that despite differences in the adsorption behavior of the biomolecules on
various soft surfaces, free energy change expressed as Bull’s free energy
change (Δ) remain nearly constant except for
BSA-fatty acid interaction which may be likely due a specific interaction.