A PROTAMINE IN A CRUSTACEAN, BALANUS-NUBILUS (CIRRIPEDIA, THORACICA) AND ITS COEXISTENCE WITH ACIDIC PROTEINS IN SPERM NUCLEI

1. The sperm nuclei of a crustacean, the giant acorn barnacle Balanus nubilus, contains a protamine very rich in lysine and moderately rich in arginine. Both amino acid residues together constitute 68 mol% of the molecule. 2. The protamine of B. nubilus coexists in the sperm nucleus with three acidic proteins. These proteins are related compositionally to what has been described previously as the unique protein in the sperm nucleus of the spider crab Libinia emarginata (Vaughn and Hinsch, J. Cell Sci. 11, 131-152, 1972). 3. B. nubilus is the first species of crustacean in which a protamine has been found.