Caseoperoxidase, mixed ?-casein-SDS-hemin-imidazole complex: a nano artificial enzyme.

ABSTRACT: A novel peroxidase-like artificial enzyme, named "caseoperoxidase", was biomimetically designed using a nano artificial amino acid apo-protein hydrophobic pocket. This four-component nano artificial enzyme containing heme-imidazole-?-casein-SDS exhibited high activity growth and k(cat) performance toward the native horseradish peroxidase demonstrated by the steady state kinetics using UV-vis spectrophotometry. The hydrophobicity and secondary structure of the caseoperoxidase were studied by ANS fluorescence and circular dichroism spectroscopy. Camel ?-casein (C?-casein) was selected as an appropriate apo-protein for the heme active site because of its innate flexibility and exalted hydrophobicity. This selection was confirmed by homology modeling method. Heme docking into the newly obtained C?-casein structure indicated one heme was mainly incorporated with C?-casein. The presence of a main electrostatic site for the active site in the C?-casein was also confirmed by experimental methods through Wyman binding potential and isothermal titration calorimetry. The existence of C?-casein protein in this biocatalyst lowered the suicide inactivation and provided a suitable protective role for the heme active-site. Additional experiments confirmed the retention of caseoperoxidase structure and function as an artificial enzyme.

SUBMITTER: Moosavi-Movahedi Z 

PROVIDER: S-EPMC5217479 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature