Five crustacean hyperglycemic family hormones of Penaeus monodon: Complementary DNA sequence and identification in single sinus glands by electrospray ionization-Fourier transform mass spectrometry

Five novel neuropeptides, designated Pm-sgp-I to -V, of the crustacean hype rglycemic hormone (CHH) family have been identified from the giant tiger pr awn Penaeus monodon by isolation of the preprohormone genes from an eyestal k complementary DNA library. On the basis of sequence similarity, the encod ed peptides have been classified as CHH-like type I hormones, which include all known CHI-Is and the molt-inhibiting hormone (MIH) of the lobster Homa rus americanus. Consistent with CHI-I type I preprohormones, the Pm-sgp pre cursors include a signal peptide, a CHH precursor-related peptide (CPRP), a nd the CHH-like hormone. Analysis by electrospray ionization-Fourier transf orm mass spectrometry enabled the neuropeptide complement of individual sin us glands to be resolved. It also confirmed the presence of the five Pm-sgp neuropeptides within the sinus gland of an individual animal, in that the masses observed were consistent with those predicted from the gene sequence of the Pm-sgps after posttranslational modification. These modifications i ncluded cleavage of the signal peptide and precursor protein, carboxy-termi nal amidation, and formation of three disulfide bridges. Analysis of crude extracts of single sinus glands from different animals revealed variation i n neuropeptide content and will provide a tool for determining whether the content varies as a function of the physiological state of the animal.