Group of small (30-50 residues), arginine-rich nucleoproteins found sporadically throughout the phylogenetic kingdom; the USP drug, the sulfate salt, is used as an antidote to heparin.

A group of simple proteins that yield basic amino acids on hydrolysis and that occur combined with nucleic acid in the sperm of fish. Protamines contain very few kinds of amino acids. Protamine sulfate combines with heparin to form a stable inactive complex; it is used to neutralize the anticoagulant action of heparin in the treatment of heparin overdose. (From Merck Index, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p692)

Protamine, simple alkaline protein usually occurring in combination with a nucleic acid as a nucleoprotein. In the 1870s Johann Friedrich Miescher discovered a protamine, salmine, in the sperm of salmon. Other typical protamines include sturine, from sturgeon, and clupeine, from herring sperm. The...