Comparative Electrochemical Behavior of Cytochrome c on Aqueous Solutions Containing Choline‐Based Room Temperature Ionic Liquids

Abstract

Ionic liquids have been attracting considerable interest in wide diverse fields, including biotechnology applications. Metalloproteins' stability in such media is still a controversial subject. Divergent reports on the metalloproteins' stability have been published, although hydrated ionic liquids seem more beneficial for achieving efficient redox transitions with the proteins' redox centers. In the present study the electrochemical behavior of Cyt c in three choline-based ionic liquids aqueous solutions, namely choline dehydrogenophosphate ([Ch][DHP]), choline 2-(N-morpholino)ethanesulfonic acid ([Ch][MES]) and choline 3-(cyclohexylamino)-1-propanesulfonic acid ([Ch] [CAPS]) was investigated. Cyt c formal potential and its temperature dependence, the diffusion coefficient and heterogeneous electron transfer rate were evaluated by cyclic voltammetry. The results show that Cyt c in aqueous solutions of [Ch][DHP] and [Ch][MES], retain its intrinsic redox properties.

Do Ionic Liquids Exhibit the Required Characteristics to Dissolve, Extract, Stabilize, and Purify Proteins? Past-Present-Future Assessment

“…Other works regarding A-ILCS of quaternary ammonium-based ILs have shown the stability and enhanced activity of Cytochrome c. − For instance, Papadopoulou et al reported the stability and a 20-fold increase in the activity of Cytochrome c in [OHC 2 NH 3 ]­[HCO 2 ] (60% in water), resulting from the high “chaotropicity” of the cation. Bhakuni et al showed the thermal stability and packaging of Cytochrome c for a month, with a 1.5-fold rise in activity in an IL-based medium comprising [Cho]­[dhp] (50%) and synthetic crowding agents, like Fycol + ethylene glycol + sucrose (5%).…”

“…Bhakuni et al showed the thermal stability and packaging of Cytochrome c for a month, with a 1.5-fold rise in activity in an IL-based medium comprising [Cho]­[dhp] (50%) and synthetic crowding agents, like Fycol + ethylene glycol + sucrose (5%). Matias et al reported the retention of intrinsic redox properties of Cytochrome c in an aqueous solution of [Cho]­[dhp] and [Cho]­[MES]. Still, with cholinium-based ILs, Bisht et al demonstrated the thermal and thermodynamic stability of Cytochrome in A-ILCS of [Cho]­[Glu]:water (50:50, w/w) under multiple stresses, such as temperature and H 2 O 2 .…”

“…Figure 15. Specificity of quaternary ammonium-based A-ILCS-protein systems [301][302][303][304][305][306][307]68. …”

Electrode Kinetics of Ion Jelly and Ion Sol-Gel Redox Materials on Screen-Printed Electrodes

“…Ionogels have also been studied as catalytic membranes by loading the material with various types of catalysts. Since some ILs work well in enhancing the activity and stability of enzymes [12,13], some ionogels are an attractive medium for biocatalysis, namely for building electrodes for enzymatic fuel cells or as biosensors [14][15][16].…”

Exploring the Effect of Choline-Based Ionic Liquids on the Stability and Activity of Stem Bromelain

“…Recently, Bisht et al 30 concluded that choline acetate [Ch] + [Ac] − is the best stabilizer, while choline hydroxide [Ch] + [OH] − acts as the destabilizer for αchymotrypsin. On the other hand, Matias et al 31 observed no considerable changes in the redox behavior of cytochrome c (Cyt c) in [Ch] + [Dhp] − . Fujita et al 32 showed no Cyt c structural modification and maintained its activity when dissolved in the [Ch] + [Dhp] − .…”