In order to improve the stability and application performance of oxalate decarboxylase (Oxdc) in the prevention and treatment of urinary calculi

chemical modification of Oxdc with ethylenediaminetetraacetic dianhydride (EDTAD) was investigated. The results of single-factor experiment showed that the extent of modification and the recovery rate of the enzymatic activity were 71.91% and 75.42%

respectively

when the reaction time was 8 h

the molar ratio of EDTAD/Oxdc was 50:1

pH 7.0

and the temperature was 37℃. The analysis results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS) indicated that Oxdc and EDTAD have been covalently bound. The ultraviolet-visible spectrum (UV) and circular dichroic (CD) measurement showed that the structure and conformation of Oxdc were tinily altered after modification by EDTAD. The enzymology changes of Oxdc were also analyzed

the results showed the optimum pH of EDTAD-modified Oxdc was shifted to the alkaline side about 1.5 unit and it had a higher thermostability. Moreover

through modification the adsorption capacity of Oxdc onto calcium oxalate monohydrate crystals was increased by 42.42%. These results suggested that the stability and application performance of Oxdc were significantly improved under this experiment.