EXPRESSION OF A HUMAN PAI-1 FUSION PEPTIDE IN ESCHERICHIA-COLI AND ITS IMMUNOCHEMICAL CHARACTERIZATION

A peptide fragment Gly(173)-Thr(232) of human plasminogen activator in hibitor (PAI-1) corresponding to beta-ribbon 3A and 3C-4C in the molec ule was synthesized as a fusion protein with beta-galactosidase Met(1) -Val(441) in E. coli. The peptide fragment was then isolated by HPLC f rom cleavage products obtained after treatment of the purified fusion protein with hydroxylamine. Specific antibodies reacting with epitopes present in PAI-1((173-232)) were then used to characterize the locati on of these epitopes in the intact PAI-1 molecule. It was found that s ome epitopes of the synthetic fragment are not expressed by intact PAI -1 indicating that this hydrophilic segment is partially hidden in lat ent form of PAI-1.