Fabrication of an in-situ co-immobilized enzyme in mesoporous silica for synthesizing GSH with ATP regeneration

We report here adopting a glucose template for synthesizing mesoporous silica for enzyme in-situ immobilization. Bifunctional GSH synthetase (GSHF) and polyphosphate kinase (PPK) were selected as model system for synthesizing GSH with ATP regeneration. Results indicated that a pore size that was slightly smaller than that of enzyme was responsible for the high performance of immobilized enzyme inside mesoporous without protein leaking. Then, the cationic dopamine was used for PPK immobilization by self-polymerization. The co-immobilized enzyme activity was much higher than that of the free enzyme. The catalytic efficiency kcat/Km of co-immobilized enzyme was higher than that of the free enzyme (8.5 and 1.5 times higher for GSHF and PPK, respectively). After optimizing the reaction parameters, the co-immobilized enzymes exhibited excellent operational and storage stability, and could be re-used seven times and retained the original activity after 30 days. It is hoped that these findings will pave the way for applying enzyme co-immobilization to biocatalytic system.