The influence of putrescine on the structure, enzyme activity and stability of α-chymotrypsin

Abstract

Information on protein stability is essential to study protein structure, activity, and interactions with ligands.

Expanding the Potential Role of Deep Eutectic Solvents toward Facilitating the Structural and Thermal Stability of α-Chymotrypsin

“…It is folded into two domains along with three intrachain and two interchain disulfide bonds. 35,41,42 In the case of native CT, far-UV CD spectra is characterized by two negative bands at 230 and 203 nm as shown in Figure 3. The shallow band ∼230 nm is intact in the presence of both the DESs along with demonstrating increased negative ellipticity.…”

“…The band for Phe is usually weaker than Trp and Tyr; thus, it often escapes recognition. 35 Since the microenvironment of each amino acid is different, analysis of the near-UV CD spectrum is a complex task. Thus, for the sake of simplicity, herein, we have principally focused on peaks around 270−310 nm characteristic of Trp and Try.…”

“…The decline in the ellipticity value is often due to the enhanced flexibility of the peptide chain around aromatic residues which may occur as a result of partial unfolding of the protein structure, 35,44 whereas elevations of positive ellipticities indicate the movement of aromatic residues toward a more asymmetric environment as a result of more compact protein structures. 34,35 Thus, these results reveal toward slight destabilization of the CT tertiary structure in the presence of lower concentrations of both DESs. Furthermore, higher concentrations (0.4−0.5 g/mL) of both ChCl-urea and ChCl-gly lead to compaction of CT structures as reflected by an intensified positive band.…”

Assessing the Compatibility of Mono-, Di-, and Tri-Cholinium Citrate Ionic Liquids for the Stability and Activity of α-Chymotrypsin

“…It contains eight tryptophan (Trp) residues, four of which (Trp 237, Trp 215, Trp 207, and Trp 172) are exposed to the solvent. Whereas, two of them (Trp 29 and Trp 27) are moderately exposed to the solvent and two (Trp l41 and Trp 5l) are entirely buried inside the hydrophobic core. − α-CT possesses unique structural and functional features for exploring the mechanism of protein folding and unfolding in different cosolvents …”

“…38−40 α-CT possesses unique structural and functional features for exploring the mechanism of protein folding and unfolding in different cosolvents. 40 Several studies have shown the effect of cosolvents including aqueous organic media, osmolytes and also different families of ILs on α-CT. 41−45 Despite numerous studies on stability and enzymatic activity of α-CT in various additives, the knowledge regarding the use of ILs with different numbers of cations per anion constant is scarce; moreover, the use of citrate anion for enzymatic stability is inadequate. Hence, meticulous research is needed to provide the understanding of the molecular mechanism for enzyme stability in vitro in the presence of ILs composed of cholinium cation and citrate anion.…”