| Co-Investigator(Kenkyū-buntansha) |
NAGASAWA Shigeharu Faculty of Pharmacentical Sciences, Hokkaido Univesity, Associate professor, 薬学部, 助教授 (70029958)
SAKAMOTO Wataru Faculty of Dentistry Hokkaido University, Associate professor, 歯学部, 助教授 (30001952)
SASAKI Makoto Nagoya City University Medical School, Professor, 医学部, 教授 (10080003)
NAKANISHI Shigetada Faculty of Medicine, Kyoto University, Professor, 医学部, 教授 (20089105)
KATORI Makoto Kitazato University School of Medicine, Professor, 医学部, 教授 (50050365)
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| Research Abstract |
Since the space of the abstract is limited, one subject performed by Iwanaga and his group will be written here.
In mammals, three kinds of kininogens, high-M_<-r> kininogen, low-M_<-r> kininogen and T-kininogen, are known and their structures and functions have been well studied. However, little is known about non-mammalian kininogens and their existence has been known only by the release of plasma kinins. In 1966, Werle et al. reported that an ornitho-kinin liberated by tissue kallikrein from chicken plasma differs from mammalian kinins in its amino acid composition. Since that, there is no report about the structure of ornitho-kinin.
In this study, ornitho-kininogen was isolated from chicken plasma by two steps with S-alkylated papain affinity and DEAE-5PW columns. The purified material gave a single band on SDS-PAGE with or without 2-mercaptoethanol and on disc-PAGE, and the M_<-r> was estimated to be 74,000 on SDS-PAGE. Ornitho-kininogen seemed to belong to mammalian high-M_<-r> kin
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inogen, based on the amino acid composition and the molecular weight, and no kininogen corresponding to low-M_<-r> kininogen and T kininogen was found in chicken plasma. In fact, ornitho-kininogen was degraded rapidly by plasma kallikrein, liberating an ornitho-kinin, and the resulting kinin was separated by reversed phase HPLC on a column of Cosmosil 5C_<18>-P. The amino acid sequence of ornitho-kinin was established to be Arg-Pro-Pro-Gly-Phe-Thr-Pro-Leu-Arg, in which the composition was different from that reported earlier by Werle et al. This sequence was similar to that of bradykinin but the two substitutions of Thr-6 and Leu-8 for Ser and Phe were found. Ornitho-kinin induced a hypotension on chicken and contracted the isolated smooth muscle. However, it did not any effect on the isolated rat uterus, suggesting that the specificity may be due to replacement of Phe-8 by Leu. The NH_2-terminal 30 amino acid residues of ornitho-kininogen exhibited 43 % identity with that of bovine kininogen. Less
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