Selective inhibition of streptokinase activation of plasminogen by aldehydes

Abstract

Summary 1. Euglobulin plasminogen lost proactivator activity and underwent changes in electrophoretic mobility when incubated in glycerol phosphate. However, spontaneous plasmin (EC 3.4.4.14) activity was not affected. 2. Formaldehyde or glyceraldehyde added to this plasminogen—glycerol phosphate solution accelerated the selective loss of proactivator activity. We found that commercial glycerol contained a sufficient amount of aldehyde to account for this effect. 3. Addition of lysine to this system inhibited the loss of proactivator activity, and plasminogen extracted according to method of Kline also did not lose proactivator activity unless more aldehyde was added to the system. We concluded that the selective loss of proactivator activity during incubation in glycerol phosphate solution was due to the reaction of aldehyde contaminants with free amino groups of euglobulin plasminogen. 4. We concluded that this loss of free amino groups prevented streptokinase activation of plasminogen by specifically inhibiting plasminogen—activator interaction