TY - JOUR KW - Computer Simulation KW - Models, Molecular KW - Peptides KW - Humans KW - Protein Binding KW - Protein Conformation KW - Thrombin KW - Reproducibility of Results KW - Antibodies, Monoclonal KW - Antibody Specificity KW - Biological Markers KW - Enzyme-Linked Immunosorbent Assay KW - Factor XIII KW - Factor XIIIa KW - Feasibility Studies KW - In Vitro Techniques KW - Protein Processing, Post-Translational KW - Thrombosis AU - V. Schroeder AU - J.-M. Vuissoz AU - A. Caflisch AU - H. P. Kohler AB -

The first step of coagulation factor XIII (FXIII) activation involves cleavage of the FXIII activation peptide (FXIII-AP) by thrombin. However, it is not known whether the FXIII-AP is released into plasma upon cleavage or remains attached to activated FXIII. The aim of the present work was to study the structure of free FXIII-AP, develop an assay for FXIII-AP determination in human plasma, and to answer the question whether FXIII-AP is released into plasma. We used ab initio modeling and molecular dynamics simulations to study the structure of free FXIII-AP. We raised monoclonal and polyclonal antibodies against FXIII-AP and developed a highly sensitive and specific ELISA method for direct detection of FXIII-AP in human plasma. Structural analysis showed a putative different conformation of the free FXIII-AP compared to FXIII-AP bound to the FXIII protein. We concluded that it might be feasible to develop specific antibodies against the free FXIII-AP. Using our new FXIII-AP ELISA, we found high levels of FXIII-AP in in vitro activated plasma samples and serum. We showed for the first time that FXIIIAP is detached from activated FXIII and is released into plasma, where it can be directly measured. Our findings may be of major clinical interest in regard to a possible new marker in thrombotic disease.

BT - Thrombosis and Haemostasis C1 - 0084 DA - 2007 Jun DO - 10.1160/TH06-08-0458 IS - 6 J2 - Thromb. Haemost. LA - eng M3 - Research Article N2 -

The first step of coagulation factor XIII (FXIII) activation involves cleavage of the FXIII activation peptide (FXIII-AP) by thrombin. However, it is not known whether the FXIII-AP is released into plasma upon cleavage or remains attached to activated FXIII. The aim of the present work was to study the structure of free FXIII-AP, develop an assay for FXIII-AP determination in human plasma, and to answer the question whether FXIII-AP is released into plasma. We used ab initio modeling and molecular dynamics simulations to study the structure of free FXIII-AP. We raised monoclonal and polyclonal antibodies against FXIII-AP and developed a highly sensitive and specific ELISA method for direct detection of FXIII-AP in human plasma. Structural analysis showed a putative different conformation of the free FXIII-AP compared to FXIII-AP bound to the FXIII protein. We concluded that it might be feasible to develop specific antibodies against the free FXIII-AP. Using our new FXIII-AP ELISA, we found high levels of FXIII-AP in in vitro activated plasma samples and serum. We showed for the first time that FXIIIAP is detached from activated FXIII and is released into plasma, where it can be directly measured. Our findings may be of major clinical interest in regard to a possible new marker in thrombotic disease.

PY - 2007 SP - 890 EP - 898 T2 - Thrombosis and Haemostasis TI - Factor XIII activation peptide is released into plasma upon cleavage by thrombin and shows a different structure compared to its bound form VL - 97 SN - 0340-6245 ER -