title: Tritium labeling of gonadotropin releasing hormone in its proline and histidine residues.
abstract: 3,4-dehydroproline9-GnRH prepared by solid phase peptide synthesis was tritiated catalytically under various conditions yielding 3H-GnRH with specific radioactivities in the range from 35-60 Ci/mmol and full LH releasing activity in vitro. Using palladium/alumina catalyst, the tritiation of the double bond occurs within ten minutes. Investigation of the tritium distribution between the amino acid residues showed a remarkably high incorporation of tritium into the histidine residue (11 to 37%). On the basis of this observation, the tritium labeling of GnRH and angiotensin I by direct catalytic hydrogen-tritium exchange was found to be useful for the labeling of these peptides at remarkably high specific radioactivity.
mesh_terms: D000537:Aluminum Oxide; D000803:Angiotensin I; D000818:Animals; D002384:Catalysis; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D006207:Half-Life; D006639:Histidine; D007553:Isotope Labeling / Q000379:methods*; D010165:Palladium; D010902:Pituitary Gland / Q000187:drug effects; D011392:Proline / Q000031:analogs & derivatives; D051381:Rats; D014316:Tritium
chemical_list: D014316:Tritium; C002195:3,4-dehydroproline; D007987:Gonadotropin-Releasing Hormone; D006639:Histidine; D010165:Palladium; D000803:Angiotensin I; D011392:Proline; D000537:Aluminum Oxide