PHYSICAL STUDIES ON PROINSULIN - ASSOCIATION BEHAVIOR AND CONVORMATION IN SOLUTION

The demonstration of a single chain biological precursor of insulin by Steiner et al. (1967a, b) and the isolation and subsequent elucidation of the amino acid sequence of porcine proinsulin by Chance et al. (1968) have led to this investigation of the physical properties of this molecule. The optical rotatory dispersion (ORD) and circular dichroic (CD) properties of proinsulin and insulin have been compared in order to gain some knowledge of the relative conformations of these proteins in solution. In addition the monomer molecular weight and association behavior of proinsulin in acid solution have been determined. The results have been interpreted in terms of a model in which the insulin moiety of the proinsulin molecule is postulated to exist in the same conformation as insulin itself. © 1968.