Protamine sulfate from salmon sperm is widely used in medical settings, particularly in the field of cardiology and surgery. Its primary application is as an antidote to heparin, a commonly used anticoagulant. After procedures like open-heart surgery or dialysis, where heparin is administered to prevent blood clotting, protamine sulfate is used to neutralize heparin's effects and restore normal blood coagulation. This helps minimize the risk of excessive bleeding post-surgery. Additionally, it is utilized in certain drug delivery systems to stabilize and prolong the release of insulin in insulin formulations, enhancing their therapeutic efficacy. Its ability to bind to nucleic acids also makes it a valuable tool in molecular biology research for studying DNA-protein interactions.