RNA-binding proteins of rabbit reticulocytes. Isolation and electrophoretic characteristics.

A complete set of RNA-binding proteins was isolated from the ribosome-free extract of rabbit reticulocytes using the method of affinity chromatography on RNA covalently coupled with Sepharose. The purity of the isolated proteins was no less than 90%. These proteins comprised about 1% of the total protein of the extract and included the main polypeptide chains of three sizes, with molecular weights of about 95000, 49000 and 36000, as well as numerous minor components. An analogous set of proteins was observed as a result of chromatography of the extract on the column with poly(U) covalently coupled with Sepharose. The protein with the molecular weight of 49000 had the highest affinity to RNA.