title: Plasmin can activate plasma prorenin but is not required for the alkaline phase of acid activation.
abstract: 1. Plasma prorenin is an inactive form of renin that is converted into active renin at alkaline pH in previously acidified plasma; this conversion of prorenin into renin is mediated by Hageman factor-dependent activation of prekallikrein, which, in turn, leads to prorenin activation. 2. Since plasma kallikrein can activate plasminogen, the present studies were designed to evaluate whether alkaline-phase activation of prorenin by plasma kallikrein is mediated via plasminogen activation. 3. We demonstrated that plaminogen is present in acid-treated plasma in sufficient quantity to convert prorenin into renin after activation by streptokinase. 4. However, alkaline-phase activation was completely normal in plasminogen-free plasma. 5. Therefore alkaline-phase activation of plasma prorenin is mediated by plasma kallikrein but is not dependent on kallikrein activation of plasminogen.
mesh_terms: D004789:Enzyme Activation; D005341:Fibrinolysin / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010958:Plasminogen; D012083:Renin / Q000097:blood*; D013300:Streptokinase / Q000378:metabolism
chemical_list: D010958:Plasminogen; D013300:Streptokinase; D005341:Fibrinolysin; D012083:Renin