MODE OF BINDING OF HISTAMINE AND SOME OTHER BIOGENIC AMINES TO A PROTAMINE-HEPARIN COMPLEX IN VITRO

Protamine and heparin form a water‐insoluble complex (PHC) at pH 7. This complex has the ability to bind sodium, histamine and monoamines electrostatically. Titrations have suggested the PHC to be formed by a linkage between the guanidino groups of the protamine and the sulphuric acid and most of the carboxylic acid groups of the heparin. The cationic binding properties of the PHC may be assigned to the terminal COO group of the protamine poly‐peptide chain. The qualitative similarities in the cationic binding properties of the PHC and rat mast cell granules are discussed, with special reference to the mechanism of histamine storage in the mast cell granules. © 1968 Scandinavian Physiological Society