Oriented adsorptive immobilization of esterase BioH based on protein structure analysis
After analyzing protein surface structure, the opposite side of the activity site of esterase BioH was observed to be hydrophilic. Hence subsequently, a hydrophilic-modified solid support was selected to immobilize enzyme through oriented adsorption. The immobilized enzyme remained 86% of its original activity under the acylation of 1-phenylethanol, much more than those immobilized on other solid supports with low hydrophilicity (20–35.6%), as the mode of the immobilization could facilitate enzyme to expose its active site to the substrate. This demonstrated that the strategy to select solid support based on the analysis of protein surface structure was successful. It was also noticed that the substrate of the reaction was obviously adsorbed onto the support, therefore the adsorption effect could not be ignored and it was necessary to obtain the adsorption isotherm of the substrate for a more authentic result. The parameter K m shifted from 884.56 to 296.09 mM after immobilization. This was possibly mainly caused by the increment of substrate concentration around the enzyme due to the substrate adsorbing on the support. It could be another explanation for why those parameters were changed after enzyme immobilization in addition to some existing proposed reasons such as stabilizing conformation, facilitating dispersion of enzyme, etc.
危险品化学品经营许可证（带存储）