title: In vitro quantitative study of the degradation of endomorphins.
abstract: The catabolism of the endomorphins was investigated in detail. The endomorphins were degraded relatively slowly in the rat brain homogenate (t1/2(endomorphin-1)=4.94 min; t1/2(endomorphin-2)=3.81 min). The inhibition of metalloproteases and aminopeptidases stabilised the endomorphins to the greatest extent. The digestion of endomorphins tritiated specifically on Tyr(1), Pro(2) or Phe(3) established also that only the aminopeptidase pathways were essential for inactivation of the endomorphins, and that the tetrapeptides were degraded by cleavage of the Pro(2)-Trp(3) or Pro(2)-Phe(3) bond. The end-products of the catabolism were amino acids; the fragments Tyr-Pro-OH and Pro-Trp-Phe-NH2 were present as intermediates. Metabolites produced by brain carboxypeptidases were not detected.
authors.affiliation: Institute of Biochemistry, Biological Research Centre of Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Tömböly
authors.forename: Antal
authors.initials: A
authors.lastname: Péter
authors.forename: Géza
authors.initials: G
authors.lastname: Tóth
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D009842:Oligopeptides / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D010649:Phenylalanine / Q000737:chemistry; D011392:Proline / Q000737:chemistry; D051381:Rats; D013997:Time Factors; D014316:Tritium / Q000378:metabolism; D014357:Trypsin / Q000737:chemistry
chemical_list: D009842:Oligopeptides; D010455:Peptides; C105293:endomorphin 1; D014316:Tritium; C105294:endomorphin 2; D010649:Phenylalanine; D011392:Proline; D000626:Aminopeptidases; D014357:Trypsin