OCCURRENCE OF LEU-LYS-BRADYKININ AND HISTIDINE-RICH PEPTIDE IN HIGH-MOLECULAR-WEIGHT KININOGEN ISOLATED FROM HORSE PLASMA

On incubation of purified horse plasma high-molecular-weight kininogen with purified plasma kallikrein, three new peptides, named fragment 1·2, fragment 1 and fragment 2, were released, in addition to the vasopeptide, bradykinin. Fragment 2 contained an extremely high level of histidine, in which eleven residues out of the total 48 residues were characterized. Thus, the result proves the existence of the histidine-rich region in horse high-molecular-weight kininogen, which is similar to the region previously identified in bovine high-molecular-weight kininogen. Moreover, we have identified a new kinin derivative, Leu-Lys-bradykinin, in horse high-molecular-weight kininogen. © 1979.