Behavior of S1- and S2-ovalbumin and S-ovalbumin A1 in urea solution: kinetics and equilibria.
The isolation of S-, S1-, and S2-ovalbumin from domestic hen egg R-ovalbumin and of two methods for S-ovalbumin A1 are described. The first is by heat treatment of R-ovalbumin A1 and the second is of R-ovalbumin followed by fractionation on Sepharose. A kinetics and equilibrium study is made of their behavior in the presence of urea and compared with that of R-ovalbumins. As anticipated, the S-ovalbumins are much more resistant to urea than R-ovalbumins. Unlike the latter, S-ovalbumins' equilibrium profiles have a simpler sigmoidal shape. The unfolding of S1- and S2-ovalbumin is an order of magnitude slower than that of R-ovalbumin. Some possible structural differences between R- and S-ovalbumin forms and their significance are discussed.
McKenzie
Hugh A
HA
School of Chemistry, University College, University of New South Wales, Australian Defence Force Academy, Canberra, Australia ACT 2600. h.mckenzie@adfa.edu.au
Frier
Robert D
RD
D000818:Animals; D002645:Chickens; D002942:Circular Dichroism; D004529:Egg White; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009905:Optical Rotatory Dispersion; D010047:Ovalbumin / Q000737:chemistry*; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D012996:Solutions / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D014508:Urea / Q000494:pharmacology*
D012996:Solutions; D014508:Urea; D010047:Ovalbumin