Studies on ox brain aminopeptides

Abstract
Mn2+-inhibited and Mn2+-activated aminopeptidases were observed in ox brain and separated from one another by DEAE- cellulose column chromatography. The Mn2+-inhibited enzyme was purified 36-fold: it exhibits a specificity forfripeptide substrates, whereas the Mn2+-activated aminopeptidase cleaves dipeptldes as well as tripeptldes. Ammonium sulphate treatment generates a Mn2+-stimulated aminopeptidase that is stable to dialysis against EDTA and water, in contrast with an endogenous Mn2+-activated preparation that is irreversibly denatured by such dialysis against EDTA and water.