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Dynamic light scattering of aqueous solutions of linear aggregates induced by thermal denaturation of ovalbumin
Author(s) -
Nemoto Norio,
Koike Akihiro,
Osaki Kunihiro,
Koseki Taihei,
Doi Etsushiro
Publication year - 1993
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.360330405
Subject(s) - chemistry , dynamic light scattering , light scattering , polymer , aqueous solution , diffusion , ionic strength , thermodynamics , denaturation (fissile materials) , static light scattering , analytical chemistry (journal) , scattering , chromatography , optics , materials science , organic chemistry , nuclear chemistry , physics , nanoparticle , nanotechnology
Dynamic light scattering measurements were performed on dilute aqueous solutions of native ovalbumin (OA) and on those of linear OA aggregates induced by thermal denaturation at low ionic strength and neutral pH. The weight‐average molecular weight M w of four aggregates tested ranged from 1,700,000 to 5,500,000. The translational diffusion coefficient D 0 of native OA at infinite dilution was estimated as 8.70 × 10 −7 cm 2 /s, which gave 56.0 Å as the diameter of the rigid spherical particle. The intensity autocorrelation function of linear OA polymers was analyzed with the cumulant method to obtain the first cumulant Λ e . The dependence of Λ e on the scattering vector q at very low polymer concentration was found intermediate between those of a flexible chain and a rigid rod. The translational diffusion coefficient D tr [≡ (T e / q 2 ) q → 0 ] was in proportion to M w −0.55 , and the magnitude was in good agreement with a value calculated from the wormlike cylinder model with values of three parameters determined in an earlier study, M L = 1600 Å −1 , d = 120 Å, and Q = 230 Å, where M L , d , and Q are the molecular weight per unit length, diameter, and persistence length, respectively. Based on these results, a new model, to be called as the dimer model , was proposed to interpret the formation mechanism of linear OA polymers induced by thermal denaturation. © 1993 John Wiley & Sons, Inc.