title: Purified factor XII has a higher specific activity than the parent molecule in plasma.
abstract: 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.
authors.affiliation: Central Hematology Laboratory, University of Bern, Inselspital, Switzerland.
authors.forename: W A
authors.initials: WA
authors.lastname: Wuillemin
authors.forename: M
authors.initials: M
authors.lastname: Furlan
authors.forename: I
authors.initials: I
authors.lastname: Huber
authors.forename: B
authors.initials: B
authors.lastname: Lämmle
mesh_terms: D000293:Adolescent; D000328:Adult; D001780:Blood Coagulation Tests; D002852:Chromatography, Ion Exchange; D016264:Dextran Sulfate; D005174:Factor XII / Q000737:chemistry / Q000302:isolation & purification* / Q000502:physiology; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing; D007616:Kaolin / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011485:Protein Binding
chemical_list: D007616:Kaolin; D005174:Factor XII; D016264:Dextran Sulfate