Partial purification and enzymatic characterization of acetylcholinesterase from the intertidal marine copepod Tigriopus brevicornis

Marine copepods such as Tigriopus brevicornis are widespread along the Atla ntic coast of Europe. These minute crustaceans are highly sensitive to cont amination and thus serve as useful bioindicators for the monitoring of poll utant effects. The use of decreased cholinesterase (ChE) activity as a subl etal biomarker of exposure to neurotoxic supposes that ChE has been defined in copepods. This study reports the partial purification, separation and c haracterization of ChE extracted from T. brevicornis. This enzyme is appare ntly an acetylcholinesterase (AChE) since it hydrolyzed acetylthiocholine i odide at a higher rate than other substrates and was inhibited by eserine b ut not by iso-OMPA. Electrophoretic studies showed that there is probably a single dimeric form defined by its apparent molecular weight (200 kDa) and sensitivity to inhibitors. The kinetic properties of this ChE were compare d with those of other invertebrate ChE. (C) 1999 Elsevier Science Inc. All rights reserved.