Assessing the Influence of Betaine-Based Natural Deep Eutectic Systems on Horseradish Peroxidase

Abstract

To validate the use of horseradish peroxidase (HRP) in natural deep eutectic systems (NADES), five different betaine-based NADES were characterized in terms of water content, water activity, density, and viscosity experimentally and by thermodynamic modeling. The results show that the NADES under study have a water activity of about 0.4 at 37 °C for water contents between 14 and 22 wt %. The densities of the studied NADES had values between 1.2 and 1.3 g.cm–3 at 20 °C. The density was modeled with a state-of-the-art equation of state; an excellent agreement with the experimental density data was achieved, allowing reasonable predictions for water activities. The system betaine:glycerol (1:2) was found to be the most viscous with a dynamic viscosity of ∼600 mPa.s at 40 °C, while all the other systems had viscosities <350 mPa.s at 40 °C. The impact of the NADES on the enzymatic activity, as well as on, conformational and thermal stability was assessed. The system betaine/sorbitol:water (1:1:3) showed the highest benefit for enzymatic activity, increasing it by two-folds. Moreover, upon NADES addition, thermal stability was increased followed by an increment in a-helix secondary structure content.

Fortification of thermal and structural stability of hemoglobin using choline chloride-based deep eutectic solvents

“…54,55 Previous work has also been explored to evaluate the stability of proteins like keratin, horseradish peroxidase, and laccase in the activity and oligomerization of rutin, a-chymotrypsin in [Ch]Cl-urea and [Ch]Cl-Gly DESs, which concluded that the stability of the proteins was conserved in both DESs. 26,48,[56][57][58] Esquembre et al 59 have demonstrated that [Ch]Cl-urea caused destabilization of the lysozyme, whereas [Ch]Cl-Gly provided stability to the protein, and similar results for[Ch]Cl-Gly have been provided by Fernandez et al 26 as the structure of the lysozyme was retained at higher concentrations in the presence of [Ch]Cl-Gly. On the other hand, Monhemi proved that [Ch]Cl-urea provided good conformational stability to lipase.…”

Uncovering biodegradability and biocompatibility of betaine-based deep eutectic systems

“…The DES prepared in this work have been designed for the evaluation of their potential as enzyme stabilizing agents (Gajardo-Parra et al 2022 ). Their use in a large industrial scale requires their full characterization not only in terms of their physico-chemical properties, but also their ecotoxicological profile.…”

“…Their use in a large industrial scale requires their full characterization not only in terms of their physico-chemical properties, but also their ecotoxicological profile. The physico-chemical characterization is presented in a previous paper (Gajardo-Parra et al 2022 ), and hence here we focus mostly on their toxicity profile.…”

Improving the activity of horseradish peroxidase in betaine-based natural deep eutectic systems

“…Throughout this work, the enzymatic activity of HRP was assessed as described elsewhere. 34 2.4. Evaluation of HRP activity and thermostability in NADES Enzyme activity of HRP was tested upon incubation in NADES for 6 h and 24 h at 37 ⁰C.…”

“…DES or IL), thinking about the final application, which significantly reduces the dependence on a great experimental effort. In a previous work from this group, 34 several betaine-based NADES were fully characterized in terms of water content and activity, viscosity and density. Moreover, the influence of these NADES in the activity and structure of HRP was also accessed.…”