Premium
Self‐association of β‐lactoglobulin A in acid solution. I. Translational diffusion coefficients
Author(s) -
Chu B.,
Yeh A.,
Chen F. C.,
Weiner B.
Publication year - 1975
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.1975.360140108
Subject(s) - histone octamer , chemistry , dimer , diffusion , stokes radius , hydrodynamic radius , dynamic light scattering , analytical chemistry (journal) , equilibrium constant , radius , ionic strength , crystallography , chromatography , thermodynamics , organic chemistry , enzyme , sedimentation coefficient , biochemistry , micelle , nanotechnology , materials science , computer security , nanoparticle , histone , computer science , nucleosome , physics , aqueous solution , gene
We report measurements of the diffusion coefficient of β‐lactoglobulin A (βLG‐A) at pH = 5.60 and 4.58 in 0.10 ionic strength acetate buffer by the techniques of analog photocurrent signal correlation and digital single‐clipped photon correlation. At a concentration of 21 mg/ml and a pH of 4.58, the self‐association of β‐lactoglobulin can be represented by a simple dimer–octamer equilibrium model. We determined the translational diffusion coefficient of the dimer and that of the octamer using the scattering results of Kumosinski and Timasheff in a dimer–octamer mixture. Our analysis shows that the dimer βLG‐A does not change its size if the pH is varied from 5.60 to 4.58 and both species remain constant in size for temperature changes from 3.5° to 25°C Hydrodynamically, the octamers behave like closed‐packed spheres with an effective radius of about 45 Å according to the Stokes‐Einstein relation.