[Identification and localization of exopeptidase activities bound to membranes of Acinetobacter calcoaceticus]

After gel filtration the supernatant of Triton X-100 treated membrane sediments of Acinetobacter calcoaceticus shows activities for alanyl aminopeptidase, leucyl aminopeptidase, glutamyl aminopeptidase, prolyl aminopeptidase, aminopeptidase My, gamma-glutamyl arylamidase, dipeptidylpeptidase IV and prolyl carboxypeptidase. The intracellular localization of the enzymes was analyzed by sucrose density gradient centrifugation of the DNase/RNase pretreated membrane sediments. Most of the exopeptidases are located in the inner membrane fractions (band L). Only gamma-glutamyl arylamidase is located with its main activity in the cytoplasmic membrane (band M). Only small exopeptidase activities could be found in the outer membrane (band H).