Effect of sucrose on the dimerization of α-chymotrypsin allowance for thermodynamic nonideality arising from the presence of a small inert solute

Sherwin K.E. and Winzor D.J. (1988) Effect of sucrose on the dimerization of α-chymotrypsin allowance for thermodynamic nonideality arising from the presence of a small inert solute. Biophysical Chemistry, 31 3: 287-294. doi:10.1016/0301-4622(88)80034-6


Author Sherwin K.E.
Winzor D.J.
Title Effect of sucrose on the dimerization of α-chymotrypsin allowance for thermodynamic nonideality arising from the presence of a small inert solute
Journal name Biophysical Chemistry   Check publisher's open access policy
ISSN 0301-4622
Publication date 1988-01-01
Sub-type Article (original research)
DOI 10.1016/0301-4622(88)80034-6
Volume 31
Issue 3
Start page 287
End page 294
Total pages 8
Subject 1303 Specialist Studies in Education
1304 Biophysics
1606 Political Science
Abstract The space-filling effects of sucrose on the dimerization of α-chymotrypsin have been investigated by sedimentation equilibrium studies on the enzyme in acetate-chloride buffer, pH 3.9, I 0.2. From the extent of enhancement of the apparent dimerization constant in the presence of 0.05-0.16 M sucrose, it is concluded that this effect of thermodynamic nonideality finds quantitative explanation in terms of excluded volume. However, the suggested approximation that the radius of an inert small solute would be sufficiently small to be neglected in the calculation of covolumes (D.J. Winzor and P.R. Wills, Biophys. Chem. 25 (1986) 243) has not withstood the more stringent test afforded by the present study of α-chymotrypsin dimerization. A value of 0.34 nm for the effective thermodynamic radius of sucrose was inferred from the covolume for self-interaction obtained by frontal gel chromatography on Sephadex G-10 under the conditions of the ultracentrifugal studies. Finally, results of sedimentation equilibrium experiments on α-chymotrypsin in the presence of 0.1 M glycerol were also shown to be consistent with interpretation in terms of the model of space-filling effects entailing complete exclusion of small solute from the hydrated protein domain.
Keyword Excluded volume
Sucrose activity coefficient
Thermodynamic nonideality
α-Chymotrypsin dimerization
Q-Index Code C1
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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