Topology-Resolved PFEP Manufacture of Linaclotide

Linaclotide is a 14-residue peptide, CCEYCCNPACTGCY, containing three disulfides with the native connectivity Cys1–Cys6, Cys2–Cys10, and Cys5–Cys13. Fifteen complete pairings are combinatorially possible for six cysteines. This paper proposes PFEP as a sequence of analytically released oxidation and exchange states, not as a source of structural information. A topology-network model compares a static one-pot oxidation with three staged windows designed to favor controlled closure and rescue of mispaired intermediates. Synthetic data predict 68.4% native linaclotide after the programmed sequence versus 42.3% for static oxidation, while unresolved/mispaired fully oxidized material falls from 35.1% to 16.2%. These values are simulations. The proposed evidence package combines differential alkylation, partial reduction, LC-HRMS/MS mapping, chromatographic separation, and bioactivity. Article type: Target-specific folding theory with synthetic topoisomer data. All numerical results labelled synthetic or modelled are hypothesis-illustration and planning outputs, not experimental measurements. No wet-laboratory experiment, validated process, clinical benefit, or shelf life is claimed.