Aim and Background: Nowadays in medical fields, the production of enzymes that are

closely associated with human health has a special position in medical research. One of the environmental problems affecting human health is environmental pollution of which organophosphorus compounds (OPs) are notable. Therefore, the detoxification of OPs is important for human health. In this field, enzymes that can degrade OPs have been identified such as OPH. OPH production with a high performance is one of the goals of protein engineering. Therefore, the use of techniques applied to measure the enzyme activity is important. Several methods by using various Ops substrates can be designed.

Material and Methods: In this study, we have used ISE to assay the degradation of DFP and spectroscopy and FPLC to assay the degradation of Diazinon and Chlorpyrifos. Then, the results were compared.

Results: The results showed that ISE is a good method in case of DFP substrate due to the production of F^- ion in presence of DFP. In the case of Chlorpyrifos and diazinon spectroscopy is more appropriate due to the changes in optical absorption of the reaction products. The FPLC method is an applicable method for all substrates.