Optimization of monomethoxy polyethyleneglycol-modified oxalate decarboxylase by response surface methodology

Abstract

In order to improve the stability of oxalate decarboxylase (Oxdc), response surface methodology (RSM), based on a four-factor three-level Box-Behnken central composite design was used to optimize the reaction conditions of oxalate decarboxylase (Oxdc) modified with monomethoxy polyethyleneglycol (mPEG5000). Four independent variables such as the ratio of mPEG-aldehyde to Oxdc, reaction time, temperature, and reaction pH were investigated in this work. The structure of modified Oxdc was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) spectroscopy, the stability of the modified Oxdc was also investigated. The optimal conditions were as follows: the mole ratio of mPEG-aldehyde to Oxdc of 1:47.6, time of 13.1 h, temperature at 29.9 °C, and the reaction pH of 5.3. Under optimal conditions, experimental modified rate (MR = 73.69%) and recovery rate (RR = 67.58%) were matched well with the predicted value (MR = 75.11%) and (RR = 69.17%). SDS-PAGE and FTIR analysis showed that mPEG was covalently bound to the Oxdc. Compared with native Oxdc, the modified Oxdc (mPEG-Oxdc) showed higher thermal stability and better tolerance to trypsin or different pH treatment. This work will provide a further theoretical reference for enzyme modification and conditional optimization.

Salicylic aldehyde-n(4)-(4-ethoxyanilinyl) thiosemicarbazone: optimization of synthesis by surface response and structural characteristics

“…Beside structuring H2L by analysis of IR, UV-Vis, MS and NMR, its acidic dissociation constants and the ability to prevent cancer cells from growing in human body were also carried out in this research. In addition, optimizing the synthesis process to find the maximum yield was estimated by using a surface response model which is an effective method to eliminate the limitations of the one-variable-at-a-time (OVAT) approach (He and Zhang, 2017;Chen, et al, 2015;Dutta et al 2015;Sabelaet al 2014;Lang et al 2006;Long et al 2017;Sarrai et al 2016;Matlob et al 2012;Somani et al 2011;Tang et al 2013).…”