Regulation of aminopeptidase activity in the sediments of a eutrophic lake

The aminopeptidase response of bacterial communities from anoxic sediments to inputs of organic matter was investigated by substrate enrichment experi ments with particulate organic matter (phytoplankton) and polymer (proteins , cellobiose and starch) and monomer (glucose and amino acids) organic comp ounds. Changes in specific aminopeptidase activity were observed over an 11 days incubation period under in situ temperatures. The pattern of this act ivity was related to polymer compounds and more precisely to enrichments wi th proteins. The results showed that monomer compounds did not inhibit acti vity. Thus, mechanisms of aminopeptidase regulation seem to be different in freshwater sediment from other aquatic environments.