Abstract
The membrane-binding characteristics of six vitamin K dependent plasma proteins, which have homologous amino acid sequences, were compared. All of these proteins display calcium-dependent membrane binding and the identified equilibria for protein-membrane binding are qualitatively the same for all proteins. Quantitative characteristics of these protein-membrane interactions allow organization into distinct subgroups. Protein C and factor VII form a subgroup which has extremely low affinity for bilayer membranes; prothrombin, factor X, and protein S form the tightest complexes with membranes and factor IX displays intermediate affinity. In the presence of manganese (which substitutes for calcium in a cation-dependent protein transition), calcium titration of protein-membrane binding shows the same calcium dependence for all proteins except prothrombin which requires lower calcium. These protein-membrane binding characteristics agree very well with the relatedness of these proteins based on their partial amino-terminal sequences.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2134-2138 |
| Number of pages | 5 |
| Journal | Biochemistry |
| Volume | 17 |
| Issue number | 11 |
| State | Published - 1978 |