CHARACTERIZATION OF BRADYKININ-RELATED PEPTIDES GENERATED IN THE PLASMA OF 6 SARCOPTERYGIAN SPECIES (AFRICAN LUNGFISH, AMPHIUMA, COACHWHIP,BULLSNAKE, GILA-MONSTER, AND GRAY MONITOR)

Incubation of heat-denatured plasma from six species occupying differe nt evolutionary positions within the Sarcopterygian lineage [the dipno an, Protopterus annectens (African lungfish); the urodele, Amphiuma tr idactylum (three-toed amphiuma); the colubrid snakes, Pituophis melano leucus sayi (bullsnake) and Masticophis flagellum (coachwhip); and the lizards Heloderma suspectum (Gila monster) and Varanus Grayi (Gray's monitor)] with trypsin generated bradykinin-related peptides that were detected by radioimmunoassay using an antiserum raised against mammal ian bradykinin (BK). The peptides were purified by HPLC and their prim ary structures were established as lungfish [Tyr(1),Gly(2),Ala(7),Pro( 8)] BK, amphiuma [Phe(1),Ile(2),Leu(5)]BK, bullsnake and coachwhip [Va l(1),Thr(6)]BK, Gila monster [Leu(2),Thr(6)]BK, and Gray's monitor [Th r(6)]BK. Monitor BK is identical to the peptide generated in turtle an d alligator plasma and coachwhip/bullsnake BK shows one amino acid sub stitution (Ala(1) --> Val) compared with the peptide generated in the plasma of the python. The data provide further evidence for the widesp read occurrence of a kallikrein-kininogen system in nonmammalian verte brates but indicate that the primary structure of BK has been poorly c onserved during evolution. (C) 1995 Academic Press.