Protamine is an alkaline protein extracted from fish sperm. It has unique physical and chemical properties and important biological functions and is widely used in medicine, food and other fields.

一. Basic properties
It is mainly extracted from mature sperm of salmon, sturgeon and other fish. Its molecular structure is rich in arginine and is strongly alkaline (isoelectric point is as high as 12-13). It can combine with acidic substances (such as heparin) to form a stable complex. It has a small molecular weight (usually 5-10 kDa), is easily soluble in water, and has good heat resistance.

二. Main application areas

1. Medical field
Anticoagulant reversal agent:
It is a specific antidote for heparin (a commonly used anticoagulant in clinical practice). When heparin is used excessively and causes bleeding, protamine quickly combines with heparin to form an inactive complex through charge neutralization, thereby restoring the blood coagulation function.
For example: in scenarios where anticoagulation is required, such as cardiac surgery and hemodialysis, protamine is often used to neutralize residual heparin after surgery.

2. As a drug carrier, it combines with nucleic acids (such as DNA) to form a complex for gene therapy or vaccine delivery; it can also be used to prepare local hemostatic agents.
Food industry
As a natural preservative and stabilizer, it is used in foods such as acidic beverages and dairy products to inhibit microbial growth or stabilize colloidal systems through charge effects.
For example: preventing protein precipitation in fruit juice drinks or extending the shelf life in meat products.

3. In molecular biology experiments, it is used to precipitate DNA or RNA (by combining with the negative charge of nucleic acids).
4. In industry, it can be used as a cationic flocculant to adsorb negatively charged pollutants in wastewater treatment.

Protamine will become an important link in the aquatic products industry chain and will be more widely used in food, medicine and other fields, making more contributions to mankind.