Reversible dimerization of avian XXXX .

@entity11850 @entity235 @entity3793 @entity2097 @entity3689 @entity3338 @entity291
The dimerization of avian @entity11850 (PP) was studied by large-zone gel chromatography using integral boundary analysis. The association constant has been determined as a function of temperature and pH. The dimerization is endothermic and entropically driven, which suggests hydrophobic interactions, and is enhanced with increasing pH. Analysis of the pH dependence indicates the involvement of ionizable groups. with pKa values of 4.5-5.5. In the avian PP molecule, there are six groups which are potentially titratable in this pH range. A comparison of the @entity3689 sequence of avian PP with that of the @entity291 and @entity235 homologues, which also exhibit pH-dependent dimerization [Noelken, M.E., Chang, P.J. _ Kimmel, J.R. (1980) Biochemistry (preceding paper in this issue)], shows that they have three @entity3338 and two @entity2097 groups in common. It is suggested that salt linkages involving these groups participate in dimerization. In the avian peptide, @entity3793 -34 may also be involved.
