IDENTIFICATION, PURIFICATION AND INITIAL CHARACTERIZATION OF THE VITELLOGENESIS-INHIBITING HORMONE FROM THE MEXICAN CRAYFISH PROCAMBARUS-BOUVIERI (ORTMANN)

1. By means of a single step of RP-HPLC on a mu-Bondapak-Phenyl column, a neuropeptide with vitellogenesis-inhibiting hormone (VIH) activity was isolated from a crude extract of sinus glands (SG) of the crayfish P. bouvieri. The yield was 5.4 ng/SG. 2. The biological activity was tested in a heterologous in vitro bioassay as the depression of vitellogenin biosynthesis by cultured Penaeus vannamei's ovaries. 3. The molecular mass was determined to be 8388 +/- 2 Da by means of mass spectrometry. 4. The N-terminus was shown to be blocked by means of the dansyl-Cl method. 5. The following amino acid average composition was obtained by means of precolumn derivatization with phenylisothiocyanate: (Asx)13, (Glx)8, (Val)7, (Arg, Cys, Leu)6, (Tyr)5, (Ala, Ile)4, (Lys)3-4, (Phe)3, (Thr)2-3, (Ser, GlY)23, (Pro)1. VIH consists of 72-74 amino acid residues. It does not contain Trp, His, or Met. 6. The tryptic peptides of the reduced and carboxymethylated VIH and of the crustacean hyperglycemic hormone (major isoform, CHH-I) were purified on an Ultrasphere-ODS column and the peptide maps compared with respect to retention times and composition. Forty-six percent of the total amount of amino acid residues were accounted for in 5 peptides which coincided in elution time and composition. 7. The remarkable resemblance between VIH and CHH-I confirms clearly that VIH belongs to the neuropeptide hormone family which includes the molt-inhibiting hormone (MIH) and the two isoforms of the crustacean hyperglycemic hormone (CHH-I and CHH-II, formerly designated CHH-B and CHH-C by us).