Conference paper

Biopolymer Adsorption, with Special Reference to the Serum Albumin-Polystyrene Latex System

J. Lyklema ; Laboratory for Physical and Colloid Chemistry of the Agricultural University, De Dreijen 6, Wegeningen, Netherlands
W. Norde ; Laboratory for Physical and Colloid Chemistry of the Agricultural University, De Dreijen 6, Wegeningen, Netherlands

Abstract

A study has been made of the adsorption of human serum
albumin (HSA) on emursifier-free, negatively charged polystyrene
(PS) latices. The adsorption has been followed directly and
microcalorimetrically. Important variables are: pH, temperature,
csalt and the surface charge a0 of the latex.
Although all adsorption isotherms have a platform, the
Langmuir theory is inadequate to account for them. Distinction
must be made between the initial stages of adsorption, solely
determined by the HSA-PS interaction and the later stages, where
lateral interaction between adsorbed HSA molecules plays also an
important role. The adsorption platform as a function of pH is maximal in the isoelectric point. Here the adsorbed amount is roughly compatible
with side-on native HSA molecules. Both below and above the
i. e. p. adsorption proceeds in a more unfolded conformation
but a spread monolayer is never reached.
The adsorption is largely driven by a net entropy gain, both
in the initial and later states of the process. Besides this, there
is a recognizable influence of the electrostatic attraction between
the latex surface and local positive excesses inside the molecule.

Keywords

Hrčak ID:

197047

URI

https://hrcak.srce.hr/197047

Publication date:

15.6.1973.

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