Purification of peptides derived from proenkephalin A on Bio-Rex 70

The weakly acidic, cation-exchange resin Bio-Rex 70 was used at a low pH for chromatography of enkephalins and other peptides containing enkephalin sequences. Recoveries of various peptide standards and peptides in adrenal chromaffin cell extracts were greater than 85%. Catecholamines and other substances such as density gradient media are not retained by the resin under the conditions employed. A significant purification of enkephalins and larger peptides containing enkephalin sequences with respect to total protein was also obtained by this method. This chromatographic technique should be useful where a low-cost, preliminary purification of samples containing peptides derived from proenkephalin A is required and may be adaptable to other peptides as well.