The peptide containing the vitamin K-dependent Ca2+ binding region of prothrombin was isolated as described by Nelsestuen, G.L., and Suttie, J. (Proc. Natl. Acad. Sci. (USA) (1973) 70, 3366-3370) and its amino acid composition reported. From the acid-base titration of the peptide, a large excess of free carboxyl groups was revealed. Quantitation of the carboxyl groups indicated eight additional carboxyls which are probably a component of the unknown prosthetic group(s) attached to the peptide. The carboxyl groups of the peptide were shown to be required for quantitative adsorption onto barium citrate and presumably for binding of Ca2+.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jul 24 1974|