Thromb Haemost 1991; 65(02): 169-173
DOI: 10.1055/s-0038-1647478
Original Article
Schattauer GmbH Stuttgart

Purified Factor XII Has a Higher Specific Activity than the Parent Molecule in Plasma

Walter A Wuillemin
The Central Hematology Laboratory, University of Bern, Inselspital, Bern, Switzerland
,
Miha Furlan
The Central Hematology Laboratory, University of Bern, Inselspital, Bern, Switzerland
,
Isabella Huber
The Central Hematology Laboratory, University of Bern, Inselspital, Bern, Switzerland
,
Bernhard Lämmle
The Central Hematology Laboratory, University of Bern, Inselspital, Bern, Switzerland
› Author Affiliations
Further Information

Publication History

Received: 08 May 1990

Accepted after revision 04 October 1990

Publication Date:
02 July 2018 (online)

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Summary

The specific clot promoting activity of factor XII (F XII) in plasma samples from 50 healthy adults was between 30 and 48 U/ mg, whereas the specific activity of purified F XII ranged from 55 to 66 U/mg. This difference was neither due to partial proteolytic activation during purification of F XII nor to the influence of plasma protease inhibitors. Purified F XII showed normal size and charge, as demonstrated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing, respectively. The increase of the specific F XII activity during the purification process mainly occurred after anion exchange chromatography on DEAE-Sephadex and after the final gel filtration step. Upon dextran sulfate activation, proteolytic cleavage of F XII and generation of kallikrein-like amidolytic activity was faster in F XII deficient plasma containing purified F XII than in F XII deficient plasma containing a corresponding amount of pooled normal plasma (NHP). The binding to kaolin was similar for both, purified F XII and plasma F XII.

In conclusion, purification alters the properties of F XII in an unknown way, resulting in an increased specific clot promoting activity.