A new kinin moiety in human plasma kininogens.
Recently, we isolated a new kinin from human urine and tentatively identified it as [Ala3]-Lys-bradykinin. However, there were inconsistencies between the properties of the naturally occurring new kinin and synthetic [Ala3]-Lys-bradykinin. In the present work, we determined whether the new kinin was released from human plasma kininogen, and further investigated the structure of the new kinin. After incubation of plasma (n = 6) with human urinary kallikrein, kinins were separated by HPLC and measured by RIA. The new kinin and Lys-bradykinin were found representing 23 +/- 3 and 76 +/- 6%, respectively, of total kinins released (2.0 +/- 0.4 micrograms/ml). The new kinin was also released from both purified low- and high-molecular-weight kininogens, representing 40-42% of total kinins released. Amino acid sequencing and composition analysis indicated that the structure of the new kinin was [Hyp3]-Lys-bradykinin (Lys-Arg-Pro-Hyp-Gly-Phe-Ser-Pro-Phe-Arg) and not [Ala3]-Lys-bradykinin. We conclude that an important proportion of human kininogens contain hydroxyproline instead of proline in position three of the bradykinin moiety.
Mindroiu
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Hypertension Research Division, Henry Ford Hospital, Detroit, MI.
Carretero
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OA
Proud
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Walz
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Scicli
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AG
D000595:Amino Acid Sequence; D001920:Bradykinin / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D007704:Kininogens / Q000097:blood*; D007705:Kinins / Q000097:blood* / Q000302:isolation & purification; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D014665:Vasodilator Agents / Q000494:pharmacology
D007704:Kininogens; D007705:Kinins; D014665:Vasodilator Agents; D001920:Bradykinin