| Title: |
Direct anticoagulant activity of protein S-C4b binding protein complex in Heerlen heterozygotes and normals |
| Authors: |
Heeb, MJ; Koenen, RR; Fernandez, JA; Hackeng, TM |
| Source: |
Heeb, MJ, Koenen, RR, Fernandez, JA & Hackeng, TM 2004, 'Direct anticoagulant activity of protein S-C4b binding protein complex in Heerlen heterozygotes and normals', Journal of Thrombosis and Haemostasis, vol. 2, no. 10, pp. 1766-1773. https://doi.org/10.1111/j.1538-7836.2004.00901.x |
| Publication Year: |
2004 |
| Collection: |
Maastricht University Research Publications |
| Subject Terms: |
anticoagulant; C4b-binding protein; factor Xa; protein S; S DEFICIENCY; FACTOR-VA; COFACTOR ACTIVITY; RISK-FACTORS; FACTOR-VIII; FACTOR-XA; SER 460; PROTHROMBINASE; PLASMA |
| Description: |
Background: Plasma protein S normally circulates free (40%) or complexed with C4b-binding protein (PS-C4BP); only free protein S is a cofactor for activated protein C during factor (F) Va inactivation. Protein S-Heerlen lacks a carbohydrate group, leading to low plasma free protein S levels, but normal levels of PS-C4BP. Objectives: Because protein S-Heerlen is not associated with thrombosis, we investigated whether PS-C4BP is directly anticoagulant in plasma and whether PS-Heerlen-C4BP has enhanced direct anticoagulant activity. Methods: An assay for protein S direct activity was applied to Heerlen-heterozygous plasmas. Free and complexed protein S were repeatedly isolated from normal and Heerlen-heterozygous plasmas and tested for direct anticoagulant activity in prothrombinase assays and in plasma. Results: Heerlen-heterozygous plasmas were deficient in free and total protein S antigen but had normal to high protein S direct anticoagulant activity. Purified Heerlen-heterozygous PS-C4BP was 7-fold more potent than normal PS-C4BP in inhibiting full prothrombinase activity, and 22-fold more potent in inhibiting prothrombin activation in the absence of FVa; it also specifically prolonged plasma clotting times 14-fold more than normal PS-C4BP. Heerlen-heterozygous PS-C4BP did not compete for limiting phospholipids any better than normal PS-C4BP. However, ligand blots and surface plasmon resonance studies showed that Heerlen-heterozygous PS-C4BP bound more avidly to FXa than did normal PS-C4BP (apparent Kd = 4.3 nM vs. 82 nM). Conclusions: Plasma-derived PS-C4BP has direct anticoagulant activity in plasma and in purified systems. Enhanced direct activity of PS-Heerlen-C4BP may compensate for low free protein S levels and low cofactor activity in individuals with protein S-Heerlen. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| ISSN: |
1538-7933; 1538-7836 |
| Relation: |
info:eu-repo/semantics/altIdentifier/wos/000224290000015; info:eu-repo/semantics/altIdentifier/pissn/1538-7933; info:eu-repo/semantics/altIdentifier/eissn/1538-7836 |
| DOI: |
10.1111/j.1538-7836.2004.00901.x |
| Availability: |
https://cris.maastrichtuniversity.nl/en/publications/2f2c6201-273a-4136-b892-fa73f0106718; https://doi.org/10.1111/j.1538-7836.2004.00901.x |
| Rights: |
info:eu-repo/semantics/openAccess |
| Accession Number: |
edsbas.A5B40C73 |
| Database: |
BASE |