Synthesis of glucose oxidase-PEG aldehyde conjugates and improvement of enzymatic stability

Abstract

In this article, aldehyde derivative of poly(ethylene glycol) (PEG) was synthesized directly with sodium periodate agent. To obtain a conjugate which possesses better stability, PEG aldehyde was bonded to native enzyme with different molar ratios. The conjugation reaction turned out to be efficient and mild. Colorimetric method was applied to evaluate the enzymatic activity of native GOD and its derivatives by introducing another enzyme, horseradish peroxidase. The GOD-PEG aldehyde conjugate with polymeric chains exhibited reduced enzymatic activity towards the catalytical oxidation of glucose, but with significantly increased thermal stability and elongated lifetime. When GOD was modified with PEG aldehyde the enzymatic activity was decreased 40% at 30 °C. However, when incubated at 60 °C the GOD-PEG aldehyde conjugate still retained the enzyme bioactivity of 40% bioactivity left after 4 h, whereas the native GOD lost almost all the activity in 4 h. The polymer chain attached, the more reduction of the enzymatic activity resulted, however, the longer the lifetime and higher thermal stability of the enzyme obtained.

Glucose Oxidase-Loaded MnFe2O4 Nanoparticles for Hyperthermia and Cancer Starvation Therapy

“…FTIR spectra of GOx@PEG-MnFe 2 O 4 confirm the loading of GOx on PEG-MnFe 2 O 4 as it exhibits the characteristic peaks of both PEG-MnFe 2 O 4 and GOx. The negatively charged nitrogen (N – ) of NH 2 groups of GOx and the positively charged (H + ) of the OH group in PEG coordinates via hydrogen bonds to form the GOx@PEG-MnFe 2 O 4 . PEG possessing hydroxyl groups through hydrogen bonding are responsible for binding interactions with the surface of magnetic NPs .…”

“…The negatively charged nitrogen (N − ) of NH 2 groups of GOx and the positively charged (H + ) of the OH group in PEG coordinates via hydrogen bonds to form the GOx@PEG-MnFe 2 O 4 . 23 PEG possessing hydroxyl groups through hydrogen bonding are responsible for binding interactions with the surface of magnetic NPs. 45 This is consistent with the FTIR results obtained.…”

“…In addition, superparamagnetic properties of the MnFe 2 O 4 NPs can be used to induce MHT in cancer cells, thereby enhancing the therapeutic efficiency. , Furthermore, polyethylene glycol (PEG), a biocompatible and hydrophilic polymer, has been commonly employed for shielding the surface of NPs from serious aggregation, opsonization, and phagocytosis. In addition, it has been proved that PEG as a stabilizing agent for GOx forms a GOx-PEG aldehyde conjugate, which enhances the enzymatic stability of GOx. , …”

Coupling and Regulation of Porous Carriers Using Plasma and Amination to Improve the Catalytic Performance of Glucose Oxidase and Catalase

“…To investigate the effect of temperature on enzyme stability, their catalytic activity at different temperatures was tested (Vardar et al, 2018). Figure 6B shows the behavior of coimmobilized and free enzymes assessed from 25 to 45 • C. The optimal temperature for free enzymes was in the range of 25-35 • C, whereas that of the co-immobilized enzymes was broader at 25-40 • C. The immobilization and modification process thus had a positive effect on enzyme stability.…”

Enhanced thermostability and catalytic efficiency of glucose oxidase in Pichia Pastoris

“…Many studies have overcome this limitation via physical, chemical or genetic modifications of nonnatural enzymes. For instance, poly (ethylene glycol) (PEG) [15], polyethylenimine (PEI) [16], and polyacrylonitrile membranes [17] have been used to immobilize GOD to improve its stability in the field of physical and chemical modifications. In the field of genetic modifications, most researchers improve the stability of enzymes through rational (computer-aided design, sequence alignment with thermophilic homologs) and irrational (error-prone PCR, gene rearrangement, etc.)…”