Chromatography of dipeptidyl aminopeptidase I on inhibitor-Sepharose columns

A number of affinity materials for the purification of dipeptidyl amino-peptidase (dipeptidylpeptide hydrolase, EC 3.4.14.1) have been prepared and tested. These material include peptide and amino acid inhibitors bound to agarose and reversible sulfhydryl adsorbents. Several of these materials are effective affinity adsorbents. The most useful material to be employed in combination with earlier purification methods is acetoxy-anilinomercuri-Sepharose. This removes proteins which are contaminants of some preparations and yields consistently high specific activities. Results with affinity and hydrophobic columns indicate that the primary interactions of the enzyme with amino acid and peptide derivative inhibitors are ionic in nature. This results is in agreement with the conclusions reached in studies of the interactions of these inhibitors with dipeptidyl aminopeptidase in solution.