Chemical synthesis of N-glycosylated insulin-like androgenic gland factor from the freshwater prawn Macrobrachium rosenbergii.

Crustacean insulin-like androgenic gland factor (IAG) of Macrobrachium rosenbergii, a heterodimeric peptide having both four disulfide bonds and an N-linked glycan, was synthesized by the combination of solid-phase peptide synthesis and the regioselective disulfide formation reactions. The disulfide isomer of IAG could also be synthesized by the same manner. The conformational analysis of these peptides by circular dichroism (CD) spectral measurement indicated that the disulfide bond arrangement affected the peptide conformation in IAG. On the other hand, the N-linked glycan attached at A chain showed no effect on CD spectra of IAG. This is the first report for the chemical synthesis of insulin-like heterodimeric glycopeptide having three interchain disulfides, and the synthetic strategy shown here might be useful for the synthesis of other glycosylated four-disulfide insulin-like peptides.