In vitro effects of pregnancy-associated plasma protein-A: artifacts due to heparin.
Pregnancy-associated plasma protein-A (PAPP-A) has been reported to inhibit elastase activity, lymphoblastogenesis, complement activity, and thrombin-induced coagulation of fibrinogen. Since some of these results are controversial, we reevaluate here the effects of PAPP-A in these last two systems. By molecular sieve chromatography, PAPP-A immunoreactivity and inhibitory activity on thrombin and complement were dissociated. A PAPP-A-free washing of the heparin-Sepharose column used during the purification of PAPP-A showed inhibitory activities similar to those of purified PAPP-A. Furthermore, a preparation of PAPP-A that had not been submitted to heparin-Sepharose chromatography during purification was not active in either assays. Thus, the anticoagulant and anti-complement effects previously attributed to PAPP-A were due to a contaminant of low molecular mass. We believe that this contaminant is probably heparin. A protocol to eliminate free and PAPP-A-bound heparin is presented herein, and implications for other previously reported in vitro effects of PAPP-A are discussed.
Meisser
A
A
Department of Obstetrics and Gynecology, University of Geneva, Switzerland.
Geinoz
A
A
Bischof
P
P
D001780:Blood Coagulation Tests; D003169:Complement Inactivator Proteins / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D006461:Hemolysis; D006493:Heparin; D006801:Humans; D011257:Pregnancy Proteins / Q000502:physiology*; D011266:Pregnancy-Associated Plasma Protein-A / Q000302:isolation & purification / Q000502:physiology*
D003169:Complement Inactivator Proteins; D011257:Pregnancy Proteins; D006493:Heparin; D011266:Pregnancy-Associated Plasma Protein-A