Physical and chemical properties of protamine from the sperm of salmon (Oncorhynchus tschawytscha). II. Anion binding characteristics.

Since the publication of a short communication (1) 4 years ago on the binding of sulfate and phosphate to salmine, considerably more information concerning the nature of the molecule is available (2-4). We now present the results of a direct determination of the anion-binding characteristics of salmine, and, in light of the physical and analytical properties, a scheme to account for the fact that out of 18 to 19 positive groups there are six binding sites with very high affinity for anions, the remaining groups having much lower binding constants.