Kallikrein generates angiotensin II but not bradykinin in the plasma of the urodele, Amphiuma tridactylum

J. M. Conlon, K. Yano

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15 Citations (Scopus)


Incubation of heat-denatured plasma from the urodele, Amphiuma tridactylum (three-toed amphiuma) or from the anurans Rana ridibunda (European green frog) and Rana catesbeiana (American bullfrog) with either glass beads, porcine pancreatic kallikrein or trypsin did not generate bradykinin-like immunoreactivity. However, peptides were generated in kallikrein-treated amphiuma plasma that contracted vascular rings from the bullfrog systemic arch and had a spasmogenic action on the bullfrog urinary bladder. These peptides, which were not generated in trypsin-treated plasma, were purified to homogeneity by reverse-phase HPLC and their primary structures established as: Asp-Arg-Val-Tyr-Val-His-Pro-Phe ([Asp1,Val5]angiotensin II) and Asn-Arg-Val-Tyr-Val-His-Pro-Phe ([Asn1,Val5]angiotensin II). Incubation of synthetic [Asn1,Val5]angiotensin II with amphiuma plasma resulted in deamidation to [Asp1,Val5]angiotensin II. The data suggest, therefore, that amphiuma plasma contains an l-asparagine amidohydrolase (asparaginase), as previously described for the eel. Although bradykinin-related peptides have been isolated from frog skin, this study provides evidence that the kallikrein-kinin system may be absent from the blood of amphibia.

Original languageEnglish
Pages (from-to)305-311
Number of pages7
JournalComparative Biochemistry and Physiology. Part C: Comparative
Issue number3
Publication statusPublished (in print/issue) - Mar 1995


  • Amphibia
  • Amphiuma
  • Angiotensin II
  • Bradykinin
  • HPLC purification
  • Kallikrein
  • Plasma
  • Vasoactive peptide


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