Activity of Organophosphate Acid Anhydrase in Rangia cuneata

Enzymes capable of hydrolyzing diisopropyl fluorophosphate (DFP) and related acetylcholinesterase inhibitors, have been reported in the tissues of many animals and have recently been renamed as organophosphate acid (opa) anhydrases. Purified clam-digestive gland was used to individually test substrate solutions of DFP and Mipafox for (opa) anhydrase activity. Results indicate three groups of molecular weight-estimates for substrate-specific enzymes within R. cuneata. When DFP was substrate, proteins in the 73,447 to 81,991 D and 20,157 opa anhydrases ranging in weight from 105,026 to 138,286 D were discovered. This data suggests multiple enzymes within R. cuneata that are strictly characterized according to substrate specificity and molecular weight.