title: Alpha 2-macroglobulin-kallikrein potentiates contact system activity: possible effect in asthma.
abstract: Bradykinin release, an end product of contact system activation, is thought to play a significant role in the pathophysiology of asthma. We have found an increased level of native alpha 2-macroglobulin-kallikrein (alpha 2M-KK) in asthma plasmas, and have demonstrated increased levels of contact system activity in these plasmas under certain laboratory conditions. We investigated the possible role of alpha 2M-KK as a modulator of the contact system activity. Alpha 2M-KK potentiated the factor XII activation on kaolin and the kallikrein production in a dextran-sulfate-mediated assay. This potentiation presumably involves a proteolytic effect of alpha 2M-KK on high molecular weight kininogen.
mesh_terms: D001249:Asthma / Q000097:blood* / Q000503:physiopathology; D016264:Dextran Sulfate; D003911:Dextrans / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005174:Factor XII / Q000378:metabolism*; D015956:Factor XIIa; D006801:Humans; D007610:Kallikreins / Q000032:analysis / Q000502:physiology*; D007616:Kaolin / Q000494:pharmacology; D007704:Kininogens / Q000502:physiology; D008722:Methods; D010446:Peptide Fragments / Q000378:metabolism; D011288:Prekallikrein / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000032:analysis / Q000502:physiology*
chemical_list: D003911:Dextrans; D007704:Kininogens; D010446:Peptide Fragments; C053069:alpha 2-macroglobulin-kallikrein complex; D000511:alpha-Macroglobulins; D007616:Kaolin; D005174:Factor XII; D016264:Dextran Sulfate; D011288:Prekallikrein; D007610:Kallikreins; D015956:Factor XIIa