Summary
Treatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in
the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the
respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions
the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions
a gradual prolongation of the one stage prothrombin time occurs without reversal.
In very diluted plasma treated with the dithiols, prothrombin can be converted into
thrombin if serum as source of active factors VII and X is added. In contrast SH factors
VII, IX and X are inactive in the specific tests. Reoxidation to active factors II,
VII, IX and X takes place during adsorption and elution of the SH derivatives. The
experiments have indicated that not only factor II but also factors VII, IX and X
have active-S-S-centres.
