特異性:MAbs 3A1 and 1G4 are directed to different antigenic determinants. MAb 3A1 reacts with the site of connection of C-peptide and C-end of B-chain of proinsulin molecule. MAbs 1D6 and 1D3 react with different epitopes on human proinsulin molecule; both of each are generated by the interactions between insulin and C-peptide parts of prohormone.