title: A common precursor to two major crab neurosecretory peptides.
abstract: The biosynthesis of proteins by the X-organ sinus gland (XOSG) neurosecretory system of the crab, Cardisoma carnifex was studied using the pulse-chase technique. Analysis of radioactive proteins following 2D-PAGE showed that during pulse incubations of less than or equal to 30 min a single predominant 14Kd prohormone was synthesized. With chase less than or equal to 3 hr the primary 14Kd protein was found to undergo differential and/or multiple post-translational modifications prior to its proteolytic cleavage. Increasing the chase to greater than 3 hr showed a shift in labeling from the 14Kd forms to 3 separate 6Kd proteins. Two of the 6Kd proteins were identified as crustacean hyperglycemic peptides (CHH). Similarity in protein labeling using [3H]leucine and [35S]cysteine suggest a second major peptide group, the H peptide, known to lack cysteine, is also contained within the 14Kd precursor. Peptide mapping of the 14Kd proteins and of unlabeled CHH and peptide H provide substantive evidence for this biosynthetic scheme. Thus, both the CHH and H peptide groups, which together constitute greater than 90% of the XOSG peptide content, in this species, arise from a common 14Kd precursor molecule.
mesh_terms: D000818:Animals; D060829:Arthropod Proteins; D003386:Brachyura / Q000502:physiology*; D003545:Cysteine / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D007447:Invertebrate Hormones / Q000235:genetics / Q000302:isolation & purification*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000302:isolation & purification; D009490:Neurosecretory Systems / Q000502:physiology; D009928:Organ Specificity; D011498:Protein Precursors / Q000235:genetics / Q000302:isolation & purification*; D011499:Protein Processing, Post-Translational; D013462:Sulfur Radioisotopes; D014316:Tritium
chemical_list: D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D009419:Nerve Tissue Proteins; D011498:Protein Precursors; D013462:Sulfur Radioisotopes; C050568:crab neurosecretory peptide common precursor; C015947:hyperglycemic hormone, crustacean; D014316:Tritium; D007930:Leucine; D003545:Cysteine