Purification and characterization of a basic 23 kDa cytosolic protein from bovine brain.

A soluble basic protein has been purified from bovine brain. It is constituted by a single polypeptide chain with a molecular weight of about 23 kDa and an isoelectric point of about 8.6. The protein was further characterized by its amino-acid composition and by a 39 amino-acid-long N-terminal sequence. Sequence homologies were demonstrated with some other cytosolic proteins. Ligand-binding assays revealed a significant affinity of the 23 kDa protein for bromosulfophthalein. Immunochemical analysis using a rabbit anti 23 kDa brain protein antiserum demonstrated its simultaneous presence in bovine liver as well as in soluble extracts from different origins (mouse and rat brain; human platelets).