Protamine sulfate, polycationic peptide and a antiheparin agent, could neutralize the anticoagulant action of heparin and enhances lipid-mediated gene transfer[1][2][3].
Protamine sulfate has an inhibitory effect on thrombin in the conversion of fibrinogen to fibrin, and that this inhibition is concentration dependent, partial, and reversible[3].Protamine sulfate is a 5-kDa cationic polypeptide derived from salmon sperm that can bind negatively charged unfractionated heparin (UFH). Protamine sulfate down-regulates thrombin generation by inhibiting factor V activation[4].
[1]. Ahmed Kouta, et al. Protamine Sulfate Neutralization Profile of Various Dosages of Bovine, Ovine and Porcine UFHs and Their Depolymerized Derivatives in Non-Human Primates. Clin Appl Thromb Hemost. Jan-Dec 2021;27:10760296211005544.
[2]. F L Sorgi, et al. Protamine sulfate enhances lipid-mediated gene transfer. Gene Ther. 1997 Sep;4(9):961-8.
[3]. R J Cobel-Geard, et al. Interaction of protamine sulfate with thrombin. Am J Hematol. 1983 May;14(3):227-33.
[4]. Fionnuala Ni Ainle, et al. Protamine sulfate down-regulates thrombin generation by inhibiting factor V activation. Blood. 2009 Aug 20;114(8):1658-65.