Involvement of protein dynamics in enzyme stability

Abstract

Dynamics of glucose oxidase immobilized and in solution were compared through their tryptophan fluorescence spectra, decay times and quenching by acrylamide. Energy barrier for thermal inactivation and melting temperature of both soluble and immobilized enzyme were also measured. Data show that the fluctuation amplitude is at the origin of protein instability. ß

Glucose Determination by Means of Steady-state and Time-course UV Fluorescence in Free or Immobilized Glucose Oxidase

“…For this reason we investigated the changes in fluorescence signals of GOD immobilized in a gelatine membrane in the presence of different glucose concentrations. As shown in Figure 2 and as reported in reference 21, the immobilization procedure does not significantly alter the spectroscopic emission spectrum of enzyme in the UV region.…”

“…Either in Figure 1a or in Figure 1b normalization has been carried out by taking as unit the maximum intensity of the recorded spectra in presence of glucose. From a comparison between curves (i) of figures 1a and 1b it is also evident that the immobilization procedure doesn't significantly alter the UV fluorescence spectra according to ref. 21.…”

Trehalose-mediated thermal stabilization of glucose oxidase from Aspergillus niger

“…6) as V max remained nearly constant (Table 3). This result suggests that large domain motions are probably absent during catalysis in glucose oxidase (Haouz et al, 2001). In contrast, it was observed a slight increase in the enzyme affinity for substrate, i.e.…”

Enzymatic biodegradable micro‐reactors for therapeutic applications

“…of GOx a new peak appears at 2 θ = 20.2° that corresponds to the reflection of maximum intensity in the diffractograms of the pure enzyme, suggesting that a portion of GOx remains crystalline inside the polymer network after the immobilization process. This result is important because the crystalline form preserves the enzyme stability for longer periods of time 29…”

“…In this study we evaluate PCL microparticles as an enzyme immobilization system that protects the enzyme, and at the same time, provides a stable, biocompatible, and biodegradable support for enzyme catalysis. Glucose Oxidase from Aspergillus niger was selected as a model enzyme to study the effect induced by the polymer network and the immobilization conditions on the enzymatic activity 29. In addition, we evaluate the enzymatic activity of the microparticles using them as biological component in a glucose amperometric biosensor.…”