Mixed SDS-Hemin-Imidazole at low ionic strength being efficient peroxidase-like as a nanozyme.

The presence of a simple surfactant, sodium n-dodecyl sulfate (SDS), at a particular concentration provided a suitable hydrophobic pocket for heme-imidazole moiety, which produced a peroxidase active site containing negative charges distributed on the colloidal surface. It is important that which aggregation structure of SDS encompasses the heme-imidazole as peroxidase active site. Ionic strength variation is an important key that can be used to obtain wide range of hydrophobic pocket in different structures. Here heme-imidazole complex was embedded into SDS micelles in different ionic strengths via phosphate buffer solution (PBS) variation and it has been investigated structurally and functionally. The critical micelle concentrations (CMC) of SDS were determined in different ionic strengths of PBS by using condutometry. The catalytic activity of triple-component: SDS-heme-imidazole, indicated that the catalytic efficiency of the novel “nanozyme” at PBS 0.2 mM was 28.7% of native horseradish peroxidase (HRP) which is related to the formation of a unique and discrete nano-structure of peroxidase-like biocatalyst at low ionic strength which obtained by Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetery (DSC) experiments. The important role of hydration layer force in assembling the particular colloid structure that causes the suitable structural thermal profile in special low PBS concentration (0.2 mM) determined by DSC method. The final biomimetic structure of micellar SDS-Heme-imidazole as an efficient artificial peroxidase as well as imidazole role on nanozyme stability was resolved by molecular dynamics simulation based on hydrodynamic radii measured by Dynamic Light Scattering (DLS). [ABSTRACT FROM AUTHOR]