Improved adsorbents for the affinity chromatography of aminopeptidases

In order to develop efficient and, at the same time, economical aminopeptidase adsorbents, derivatives of 3-amino-2-hydroxy-4-phenylbutanoic acid (Ahp) were examined in view of a prospective use as immobilized ligands. In addition, some methods of linking these compounds to aminohexyl-Sepharose were critically compared. It turned out that highest yields can be obtained by carbodiimide coupling of unprotected tripeptides containing C-terminal glycine. A material of this type, (2S,3S)-Ahp-Val-Gly-aminohexyl-Sepharose, proved to be an excellent affinity absorbent for two rather dissimilar aminopeptidases from yeast. The enzymes were strongly bound, even under unfavourable conditions, but were readily eluted again by low concentrations of Zn2+.