Metal ions coordinated immobilization of phenylalanine dehydrogenase by GO‐PEI with high activity recovery and enhanced stability

Abstract

BACKGROUND Dehydrogenases dependent on NAD(P)H are widely applied for biosynthesis of chiral chemicals. However, they are unstable and easy denaturated compared with hydrolases. A new strategy for dehydrogenases immobilization with the advantages of easy operation and high activity recovery should be developed. Biocompatible hybrid materials (GO‐PEI‐M) have been obtained by metal ions coordinated polyethylenimine (PEI) functionalized graphene oxide (GO). RESULTS The immobilized enzyme recovery rates of GO‐PEI‐Mg (magnesium ion coordinated GO‐PEI) and GO‐PEI‐Mn (manganese ion coordinated GO‐PEI). In addition, the stability of GO‐PEI‐Mn‐PheDH (Phenylalanine Dehydrogenase) and GO‐PEI‐Mg‐PheDH was greatly improved, and it maintained 65% and 79% activity, respectively, after seven times reuse. In addition, the stability of GO‐PEI‐Mn‐PheDH (Phenylalanine Dehydrogenase) and GO‐PEI‐Mg‐PheDH was greatly improved. After seven times reuse, GO‐PEI‐Mn‐PheDH and GO‐PEI‐Mn‐PheDH and maintained 65% and 79% activity, respectively. An assembly mechanism was proposed from the perspectives of multi‐level interactions, including hydrogen bonding, electrostatic forces, and coordinated bonds. CONCLUSION GO‐PEI‐Metal ion hybrid materials offer a promising carrier for enzyme immobilization with the advantages of biocompatibility and relatively strong interaction. © 2020 Society of Chemical Industry

Immobilized Dipeptidase in Manganese Ion-Loaded Polyethylenimine-Induced Calcium Phosphate Nanocrystals for Carnosine Synthesis

“…Moreover, the steric hindrance and diffusion resistance for the substrate could also result in a decrease in enzyme activity. 37 The K m values of free PepD and PepD-Mn-PEI@CaP were 168.5 and 105.2 mM, respectively. The decrease in the K m value indicates that the immobilized PepD had higher affinity for the substrate.…”

“…Additionally, PEI could bind Mn 2+ in solution, facilitating its contact with the enzyme near PEI and playing an activating role. 37 Therefore, PEI-induced biomimetic mineralization was utilized in this study for constructing stable immobilized PepD.…”

“…This increase in activity could be attributed to the positive charge abundance of PEI in the reaction system at pH 8.0, which electrostatically interacted with the negatively charged PepD. Additionally, PEI could bind Mn 2+ in solution, facilitating its contact with the enzyme near PEI and playing an activating role . Therefore, PEI-induced biomimetic mineralization was utilized in this study for constructing stable immobilized PepD.…”

“…Immobilization might lead to conformational changes in the enzyme, thereby impairing the enzyme activity. Moreover, the steric hindrance and diffusion resistance for the substrate could also result in a decrease in enzyme activity . The K m values of free PepD and PepD-Mn-PEI@CaP were 168.5 and 105.2 mM, respectively.…”

Research Advances in Regulating the Microenviroment of Enzyme Electrodes in Non‐aqueous Systems: A Minireview

“…Discovering novel amine dehydrogenases from organisms from extremophiles can lead to the development of biosensors for aromatic amine detection [49][ 50] . Immobilization of hyperthermophilic and halophilic phenylalanine dehydrogenase into conductive hybrid materials such as GO-PEI can be further used for amino acid bioelectrosynthesis [51].…”