Natural and synthetic chiral isoforms of crustacean hyperglycemic hormone from the crayfish Astacus leptodactylus: hyperglycemic activity and hemolymphatic clearance.
In the crayfish Astacus leptodactylus, as in several crustacean species, the crustacean hyperglycemic hormone is present as two isoforms differing by the chirality of the third residue, a phenylalanine. In the present work, isoforms synthesized full length by solid-phase peptide synthesis have been purified, refolded, the location of the disulfide bridges has been checked, their immunoreactivity against different antibodies have been analyzed and their hyperglycemic activity tested, to ensure the identity of the synthetic peptides with their natural homologs. Different parameters of the hyperglycemic activity of both isoforms were studied. In addition to a difference in the kinetics of hyperglycemia, already known from other studies, it was observed that the dose-response was different depending on the season where experiments were performed, the response being stronger in spring than in autumn, especially for the d-Phe containing isoform. A dosage method based on sandwich enzyme linked immunosorbent assay (ELISA) has been developed to measure hemolymphatic levels of the isoforms after spiking of the animals with one isoform or the other. It was found that hemolymphatic clearance was identical for both isoforms, indicating that their differential effect is not linked to their different lifetime in the hemolymph but may rather rely on other mechanisms such as their binding to different target tissues.
Université Pierre et Marie Curie, Paris cedex 05, France. flebaupain@laposte.net
Florence
F
Lebaupain
Maryse
M
Boscameric
Eric
E
Pilet
Daniel
D
Soyez
Nédia
N
Kamech
D000818:Animals; D060829:Arthropod Proteins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D003400:Astacoidea / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006458:Hemolymph / Q000378:metabolism*; D007447:Invertebrate Hormones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013058:Mass Spectrometry; D009419:Nerve Tissue Proteins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D020033:Protein Isoforms / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D060327:Solid-Phase Synthesis Techniques
D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; C015947:hyperglycemic hormone, crustacean