Detection by Fluorescence of Structural Changes Accompanying the Activation of Hageman Factor (Factor XII)

Bd, Fair; Saito, H; Od, Ratnoff; Wb, Rippon

doi:10.3181/00379727-155-39773

Cited by 26 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to this traditional biochemical theory, FXII “binds” to a surface (represented by the grey box) bearing negatively-charged functional groups through domains rich in positively-charged lysine residues [100, 101]. Binding purportedly induces a conformational change in FXII, ultimately leading to a transformation into an active-enzyme form FXIIa through a process known as autoactivation [102, 103]. Structural changes of FXII upon binding is thought to sharply increase susceptibility to proteolytic cleavage by Kal [104].…”

Section: Figures and Tablementioning

confidence: 99%

Contact activation of blood-plasma coagulation

2009

View full text Add to dashboard Cite

This opinion identifies inconsistencies in the generally-accepted surface biophysics involved in contact activation of blood-plasma coagulation, reviews recent experimental work aimed at resolving inconsistencies, and concludes that this standard paradigm requires substantial revision to accommodate new experimental observations. Foremost among these new findings is that surfacecatalyzed conversion of the blood zymogen factor XII (FXII, Hageman factor) to the enzyme FXIIa ( , a.k.a. autoactivation) is not specific for anionic surfaces, as proposed by the standard paradigm. Furthermore, it is found that surface activation is moderated by the protein composition of the fluid phase in which FXII autoactivation occurs by what appears to be a protein adsorption-competition effect. Both of these findings argue against the standard view that contact activation of plasma coagulation is potentiated by assembly of activation-complex proteins (FXII, FXI, prekallikrein, and high-molecular-weight kininogen) directly onto activating surfaces (procoagulants) through specific protein/surface interactions. These new findings supplement the observation that adsorption behavior of FXII and FXIIa is not remarkably different from a wide variety of other blood proteins surveyed. Similarity in adsorption properties further undermines the idea that FXII and/or FXIIa are distinguished from other blood proteins by unusual adsorption properties resulting in chemically-specific interactions with activating anionic surfaces.

show abstract

Section: Figures and Tablementioning

confidence: 99%

Contact activation of blood-plasma coagulation

2009

View full text Add to dashboard Cite

show abstract

“…The intrinsic system is activated when factor XI1 binds to collagen at the vessel injury site (Wilner et al 1968, Osterud 1984. The bound factor XI1 undergoes conformational change and probably slow autoactivation (Fair et al 1977, Tans et al 1983. The small amount of XII, formed cleaves prekallikrein to yield kallikrein.…”

Section: H Docandh H Cmentioning

confidence: 99%

The biochemistry of haemostasis

Gonias

Pizzo

1986

Clinical &Amp; Laboratory Haematology

View full text Add to dashboard Cite

“…Ratnoff and Saito (11) have also recently suggested that Sephadex-Ellagic acid mixtures may activate HF without proteolytic modification. That conformational changes do occur in surface-bound HF was supported by finding increased hydrophobicity (12) and a change in the circular dichromatic spectum (13) of HF upon binding to negatively charged substances. Other workers, however, have concluded that binding of HF to a surface per se, is not alone sufficient to activate the molecule but that limited cleavage is also required for HF activation.…”

mentioning

confidence: 92%

The autoactivation of rabbit hageman factor

Wiggins

Cochrane

1979

The Journal of Experimental Medicine

View full text Add to dashboard Cite

Proteolytic cleavage and activation of isolated, single chain, zymogen Hageman factor was observed in the presence of kaolin alone. The rate of cleavage of kaolin-bound Hageman factor was enhanced 50-fold by the presence of prekallikrein and high molecular weight kininogen. The two-chain 82,000 dalton form of activated Hageman factor (α-HF(a)) also cleaved kaolin- bound single-chain Hageman factor in a dose-dependent manner, yielding fragments of 28,000 and, 50,000 dahons under reducing conditions. Cleavage of kaolin-bound single-chain Hageman factor was not inhibited by preincubation with diisopropylfluorophosphate (12 mM) for 10 min, but long-term incubation of Hageman factor with diisopropylfluorophosphate (up to 48 h) resulted in inhibition of cleavage of kaolin-bound Hageman factor to an extent proportional to the inhibition of procoagulant Hageman factor activity. Hageman factor cleavage was maximal when the kaolin concentration was {approximately} 10-fold greater than the Hageman factor concentration (wt:wt), and was partially inhibited by high molecular weight kininogen. Kaolin-bound Hageman factor cleaved clotting factor XI in an amount which correlated with the extent of cleavage of the Hageman factor. These findings are compatible with the concept that single-chain Hageman factor and α- HF(a), are both capable of cleaving and activating kaolin-bound Hageman factor and that a close molecular association of kaolin-bound Hageman factor molecules is required for this reaction.

show abstract

Detection by Fluorescence of Structural Changes Accompanying the Activation of Hageman Factor (Factor XII)

Cited by 26 publications

References 0 publications

Contact activation of blood-plasma coagulation

Contact activation of blood-plasma coagulation

The biochemistry of haemostasis

The autoactivation of rabbit hageman factor

Contact Info

Product

Resources

About