Identification and comparison of the organophosphate acid anhydrase activities of the clam,Rangia cuneata

1. Tissue extracts of the commonly found brackish water clam Rangia cuneata were found to degrade the potent neurotoxin diisopropylfluorophosphate (DFP) and surprisingly N, N′-diisopropylphosphorodiamidofluoridate (mipafox).2. Results indicate two groups of molecular weight-estimates for substrate specific enzymes within the digestive gland of R. cuneata. When DFP was a substrate, a protein in the range of 30,500–21,300 D was identified as OPA anhydrase. With mipafox as substrate, an OPA anhydrase ranging in weight from 105,000 to 138,300 D was identified.3. This data suggests at least two forms of active OPA anhydrase type proteins are active within R. cuneata. Suggestions as to the natural role of the OPA anhydrases and the implications in predicting environmental toxicity and in hazardous waste site clean up are discussed.