TABLE 2.
N-terminal sequencing of thrombin cleavage products for the thrombin-AT complex
Sequences marked with * are unique sites that only occur in thrombin when in complex with AT. Multiple N termini are generally observed for each band due to disulfide bonds and the covalent bond between Ser195 of thrombin and Arg393 of AT. Cleavage at the very C terminus of thrombin (e.g. exosite II residues Arg233, Lys235, Lys236, and Lys240) would produce bands too small to detect by SDS-PAGE and may therefore have been missed.
| Band ID | Sequence | Origin of sequence |
|---|---|---|
| a | YNWREN* | Thrombin, H chain, Arg93 cut |
| a | TFGSGE | Thrombin, L chain, N terminus |
| a | HGSPVD | AT, N terminus |
| a | SLNPNR | Cleaved AT, C-terminal fragment |
| b | SLNPNR | Cleaved AT, C-terminal fragment |
| b | HGSPVD | AT, N terminus |
| b | GQPSV | Thrombin, H chain, Lys149 cut |
| b | VTGWGN* | Thrombin, H chain, Arg137 cut |
| c | IVEGSD | Thrombin, H chain, N terminus |
| c | TFGSGE | Thrombin, L chain, N terminus |
| d | IVEGSD | Thrombin, H chain, N terminus |
| e | IVEGSD | Thrombin, H chain, N terminus |
| e | GQPSV | Thrombin, H chain, Lys149 cut |
| f | YNWREN* | Thrombin, H chain, Arg93 cut |
| f | TFGSG | Thrombin, L chain, N terminus |
| f | KSPQEL* | Thrombin, H chain, Arg35 cut |
| g | YNWREN* | Thrombin, H chain, Arg93 cut |
| g | TFGSGE | Thrombin, L chain, N terminus |
| h | IGKHSR* | Thrombin, H chain, Arg67 cut |
| h | TRYER* | Thrombin, H chain, Arg73 cut |
| h | HSRTR* | Thrombin, H chain, Lys69 cut |
| i | TRYER* | Thrombin, H chain, Arg73 cut |
| i | HSRTRY* | Thrombin, H chain, Lys69 cut |
| i | IGKHSR* | Thrombin, H chain, Arg67 cut |