Ovine prolactin: equilibrium characteristics of the recombinant molecule formed by noncovalent interaction of two fibrinolysin fragments by fluorescence polarization.

Abstract

The equilibrium characteristics of the recombined molecule formed by noncovalent interaction of two fibrinolysin fragments of ovine prolactin (oPRL) have been studied with fluorescence polarization. Fluorescein isothiocyanate (isomer I) was used to label oPRL-(1-53), creating a fluorescent peptide indistinguishable from the unlabeled fragment inthe complementation reaction with oPRL-(54-199). The dissociation constant of the recombinant prolactin was 0.144 ,uM at 30°C, with a free energy of dissociation of 9.50 kcal/mol.