Abstract
We have isolated and characterized two forms of soluble thrombomodulin from human urine. The purification procedure consisted of ultrafiltration, chromatography on DEAE-Sepharose, affinity chromatography on diisopropyl-phosphate-thrombin and/or monoclonal anti-thrombomodulin IgG affigel followed by reverse-phase HPLC. An active soluble form of thrombomodulin was purified 1600-fold from 34-1 urine. The purified protein migrated as a doublet, with molecular mass 76/72 kDa under reducing conditions and 63/57 kDa under non-reducing conditions as determined by SDS/PAGE. Amino acid analysis of the 63/57-kDa soluble thrombomodulin confirmed sequence identity with human thrombomodulin and demonstrated N-terminal heterogeneity. Compared to membrane-type thrombomodulin, the purified 63/57-kDa soluble thrombomodulin was more active as a cofactor for protein-C activation. The second major thrombomodulin fragment in urine is an inactive 35-kDa thrombomodulin polypeptide derived from the N-terminal extracellular region of thrombomodulin.
| Original language | English |
|---|---|
| Pages (from-to) | 1079-1087 |
| Number of pages | 9 |
| Journal | European Journal of Biochemistry |
| Volume | 221 |
| Issue number | 3 |
| Publication status | Published - 1994 |