Amino Acid Composition of Human Plasma Prothrombin

Calcium-dependent changes in properties of human prothrombin: a study using high-performance size-exclusion chromatography and gel-permeation chromatography

High-performance size-exclusion chromatography using a TSK 3000 SW column and aqueous gel filtration with Sephacryl S-200 SF have been used to characterize the effects of calcium ions on the hydrodynamic properties of human prothrombin and prethrombin 1. The results suggest that the effective hydrodynamic radius of prothrombin is less in the presence than in the absence of calcium ions. In addition, when using the TSK-3000 SW column, Ca2+-dependent formation of a hydrophobic site in the fragment 1 region of prothrombin results in an apparent further decrease in hydrodynamic radius.

Prothrombin complex concentrates for clinical use

Prothrombin complex concentrates prepared for clinical use are reviewed with emphasis on frequently observed adverse reactions such as viral hepatitis and thromboembolic complications. Preparation procedures and quality control are described briefly, and the use of these concentrates in the treatment of hemophilia A patients who develop factor VIII inhibitors is also described. The causes of and methods for the detection of potential thrombogenicity are discussed and suggestions which may result in a safer product are made.

Improved procedures for the purification of selected vitamin K-dependent proteins

Improved methods are described to obtain bovine prothrombin, Factor IX, Protein C, and autoprothrombin III (Factor X, Auto-III) in purified form. The prothrombin had a specific activity of 4,340 Iowa units/mg. Theoretically, a preparation of clean thrombin should have a specific activity of 8,200 U/mg, because 47.08% of the protein in prothrombin is lost when thrombin forms. Such thrombin preparations have been obtained (Arch. Biochem. Biophys. 121, 372 (1967)). The prothrombin concentration of bovine plasma is near 60 mg/liter. Protein C, first isolated by Stenflo (J. Biol. Chem. 251, 355 (1976)), was found to be the precursor of autoprothrombin II-A (Auto-II-A), discovered earlier (Thromb. Diath. Haemorrh. 5, 218 (1960)). Protein C (Factor XIV) was converted to Auto-II-A (Factor XIVa) by thrombin. Digesting purified Auto-III with purified thrombin removed a small glycopeptide from the COOH-terminal end of the heavy chain to yield Auto-IIIm. Auto-III thrombin leads to Auto-IIIm + peptide. Auto-IIIm was not converted to the active enzyme with thromboplastin, and furthermore, inhibited the activation of purified native Auto-III with thromboplastin. Auto-IIIm was also not converted to the active enzymes when the procoagulants consisted of purified Factor VIII, purified Factor IXa, platelet factor 3 and calcium ions. The "activation peptide" released by RVV-X from the NH2-terminal end of the heavy chain and the active enzyme (Auto-Cm) were purified. Auto-III was also activated with purified RVV-X. The same "actid of Auto-Cm. Purified Factor IX developed anticoagulant activity when reacted with an optimum concentration of purified thrombin. A suitable reagent for the assay of Factor IX was prepared by removing prothrombin complex from anticoagulated bovine plasma and restoring the prothrombin and Auto-III concentration with use of the respective purified proenzymes.

The influence of cadmium ions on the adsorption of prothrombin onto A1(OH)3 as a means to purify prothrombin

1. In the presence of CdSO4(1mM),Al(OH)3(1.3% w/v) completely adsorbs the coagulation factors VII, IX, and X from normal plasma, but factor II (prothrombin) is adsorbed for about 50% only.2. A purification procedure for factor II is developed, using Al(OH)3 adsorption in the presence of Cd2+ as a first step and using column chromatography only once. A 750-fold purification is obtained at a 24% yield. 3. Comparison of the prothrombin thus obtained, with prothrombin isolated by the method of Kisiel and Hanahan (Biochim. Biophys. Acta (1973) 304, 103-113) does not show significant differences in amino acid composition, N-terminal amino acid, molecular weight or immunological properties. 4. Comparison of the two prothrombin preparations in a thrombin-generating system shows that although the final yield of thrombin from a given amount of prothrombin in both preparations is the same, the initial velocity of thrombin formation from our preparation is comparable to that of native prothrombin, whereas the other preparation is converted significantly slower.