Autoactivation of blood factor XII at hydrophilic and hydrophobic surfaces

Rui Zhuo, Christopher A. Siedlecki, Erwin A. Vogler

Research output: Contribution to journalArticlepeer-review

95 Scopus citations


Contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution is shown not to be specific for anionic hydrophilic procoagulants as proposed by the accepted biochemistry of surface activation. Rather, FXII activation in the presence of plasma proteins leads to an apparent specificity for hydrophilic surfaces that is actually due to a relative diminution of the FXII→FXIIa reaction at hydrophobic surfaces. FXII activation in neat-buffer solution was effectively instantaneous upon contact with either hydrophilic (fully water-wettable clean glass) or hydrophobic (poorly water-wettable silanized glass) procoagulant particles, with greater FXIIa yield obtained by activation with hydrophobic procoagulants. In sharp contrast, both activation rate and yield was found to be significantly attenuated at hydrophobic surfaces in the presence of plasma proteins. Putative FXIIa produced by surface activation with both hydrophilic and hydrophobic procoagulants was shown to hydrolyze blood factor XI (FXI) to the activated form FXIa ( FXI over({long rightwards arrow}, FXIIa) FXIa ) that causes FXI-deficient plasma to rapidly coagulate.

Original languageEnglish (US)
Pages (from-to)4325-4332
Number of pages8
Issue number24
StatePublished - Aug 2006

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials


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