Ion exchange chromatography of prolactin in urea-containing buffers.

Moore and Stein (1) have reviewed the work of Boardman and Partridge and others on problems encountered in attempting the chromatography of nonbasic proteins on Amberlite IRC-50 by elution analysis with the use of buffers of constant composition for the elution. Boardman and Partridge (2) suggested that the difficulty in achieving reversible equilibrium binding was due to hydrogen bonding between the protein and the resin. For this reason recent attempts to subject nonbasic proteins to this type of elution analysis on this resin have involved the addition of urea to the buffers used for elution. In this way successful chromatography was achieved with insulin (3) and glucagon (4). The present report deals with the extension of elution analysis with the use of urea-containing buffers of constant composition to the chromatography of prolactin, a larger protein than insulin or glucagon. In addition to providing a technique for the fractionation and analysis of prolactin, this system provides an opportunity to test the effect of protein molecular weight on the chromatographic system by comparing the behavior of prolactin with that of insulin as reported earlier (3).