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Concentration dependence of proteoglycan diffusion
Author(s) -
Harper Gregory S.,
Comper Wayne D.,
Preston Barry N.,
Daivis Peter
Publication year - 1985
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360241111
Subject(s) - chemistry , diffusion , proteoglycan , dynamic light scattering , light scattering , relaxation (psychology) , population , biophysics , scattering , thermodynamics , optics , biochemistry , nanotechnology , materials science , psychology , social psychology , physics , demography , sociology , biology , nanoparticle , extracellular matrix
The mutual diffusion coefficient of the bovine nasal cartilage proteoglycan subunit is found to increase rapidly with increasing concentration and decreasing ionic strength. These results have been obtained by analysis of the boundary relaxation of concentration gradients in the analytical ultracentrifuge by schlieren optics. The diffusion behavior can be understood in terms of the nonideality of the proteoglycan. The magnitude of the nonideality is dominated by charge interactions, whereas the influence of molecular size and associated excluded‐volume interactions is small. The concentration dependence of the apparent diffusion coefficient of the proteoglycan subunit from dynamic light scattering was found, in contrast, to decrease with increasing concentration. Computer simulation of the dynamic light scattering suggests that the presence of a small population of aggregates may account for the difference in the two types of diffusion measurement due to their marked influence on the scattering.