Talesa_2002_Environ.Toxicol.Chem_21_102

The benthic mollusk Scapharca inaequivalvis was collected in spring 1999 from three areas of the northern Adriatic Sea From the mollusk molecular forms of acetylcholinesterase AChE consisting of two prevailing spontaneously soluble SS forms present in the blood were obtained These forms are a globular tetramer SSG4 a dimer SSG2 of catalytic subunits and a minor amphiphilic globular dimer low-salt Triton LST G2 phosphatidylinositol tailed All SS and LST forms partially purified by affinity chromatography are AChEs with a marked substrate specificity for acetylthiocholine and poor hydrolysis with butyrylthiocholine They are poorly inhibited by carbamate eserine and show a different pattern of inhibition by organophosphate diisopropylfluorophosphate DFP with totally resistant SS forms from clams collected from the two stations nearest the Po River Acetylcholinesterase SS and LST forms are expressed at highest lowest and middle levels in clams collected from the northern station closer to the Po delta and from the two more southern ones respectively The possibility that the expression pattern of AChE forms is due to effects of single or mixed classes of chemical pollutants is discussed