Protamine sulfate
（重定向自Protamine sulphate）
Protamine sulfate is a drug that reverses the anticoagulant effects of heparin by binding to it.
Protamine was originally isolated from the sperm of salmon and other species of fish but is now produced primarily through recombinant biotechnology. It is a highly cationic peptide that binds to either heparin or low molecular weight heparin (LMWH) to form a stable ion pair, which does not have anticoagulant activity. The ionic complex is then removed and broken down by the reticuloendothelial system. In large doses, protamine sulfate may also have an independent—however weak—anticoagulant effect.