The activation of the alternative pathway C3 convertase by human plasma kallikrein

Immunology. 1982 Mar;45(3):587-95.


Human plasma kallikrein can replace factor D for the activation of the alternative pathway C3 convertase of human complement. The factor B cleavage patterns by factor D and kallikrein are indistinguishable. The ability of kallikrein to cleave factor B is influenced by the magnesium ion concentration and the C3b concentration. Factor D is about ten-fold more effective on a molar basis, for the alternative pathway C3 convertase activation than is kallikrein. The physiological role of the action of kallikrein on the alternative pathway C3 convertase is discussed.

MeSH terms

  • Centrifugation, Density Gradient
  • Chromatography, Gel
  • Complement Activating Enzymes / metabolism*
  • Complement Activation / drug effects*
  • Complement C3-C5 Convertases / metabolism*
  • Complement Factor B / metabolism
  • Complement Factor D / pharmacology
  • Complement Pathway, Alternative / drug effects*
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation / drug effects
  • Humans
  • Kallikreins / antagonists & inhibitors
  • Kallikreins / blood
  • Kallikreins / pharmacology*


  • Complement Activating Enzymes
  • Complement C3-C5 Convertases
  • Kallikreins
  • CFD protein, human
  • Complement Factor D
  • Complement Factor B