17423-63-1Relevant articles and documents
Two oxidation sites for low redox potential substrates: A directed mutagenesis, kinetic, and crystallographic study on pleurotus eryngii versatile peroxidase
Morales, María,Mate, María J.,Romero, Antonio,Martínez, María Jesús,Martínez, ángel T.,Ruiz-Due?as, Francisco J.
, p. 41053 - 41067 (2012)
Versatile peroxidase shares with manganese peroxidase and lignin peroxidase the ability to oxidize Mn2+ and high redox potential aromatic compounds, respectively. Moreover, it is also able to oxidize phenols (and low redox potential dyes) at two catalytic sites, as shown by biphasic kinetics. A high efficiency site (with 2,6-dimethoxyphenol and p-hydroquinone catalytic efficiencies of ～70 and ～700 s-1 mM-1, respectively) was localized at the same exposed Trp-164 responsible for high redox potential substrate oxidation (as shown by activity loss in the W164S variant). The second site, characterized by low catalytic efficiency (～3 and ～50 s-1 mM-1 for 2,6-dimethoxyphenol and p-hydroquinone, respectively) was localized at the main heme access channel. Steady-state and transient-state kinetics for oxidation of phenols and dyes at the latter site were improved when side chains of residues forming the heme channel edge were removed in single and multiple variants. Among them, the E140G/K176G, E140G/P141G/K176G, and E140G/W164S/K176G variants attained catalytic efficiencies for oxidation of 2,2′-azino-bis(3- ethylbenzothiazoline-6-sulfonate) at the heme channel similar to those of the exposed tryptophan site. The heme channel enlargement shown by x-ray diffraction of the E140G, P141G, K176G, and E140G/K176G variants would allow a better substrate accommodation near the heme, as revealed by the up to 26-fold lower Km values (compared with native VP). The resulting interactions were shown by the x-ray structure of the E140G-guaiacol complex, which includes two H-bonds of the substrate with Arg-43 and Pro-139 in the distal heme pocket (at the end of the heme channel) and several hydrophobic interactions with other residues and the heme cofactor.
An iron(iii) tetradentate monoamido complex as a nonheme iron-based peroxidase mimetic
Hitomi, Yutaka,Hiramatsu, Kazuaki,Arakawa, Kengo,Takeyasu, Toshiyuki,Hata, Masashi,Kodera, Masahito
, p. 12878 - 12882 (2013)
A mononuclear iron(iii) complex of a noncyclic tetradentate monoamido ligand, Fe(iii)mpaq, catalyses the oxidation of Orange II, guaiacol, ABTS and Amplex Red with H2O2 in aqueous solutions at neutral pH. Under identical conditions, other structurally related nonheme iron complexes showed only negligible activities.
Cytochrome: C -poly(acrylic acid) conjugates with improved peroxidase turnover number
Benson,Gorecki,Nikiforov,Tsui,Kasi,Kumar
, p. 4043 - 4048 (2019)
Cytochrome c-poly(acrylic acid) (cyt c-PAA) conjugates with 34-fold enchancement in peroxidase turnover number (kcat) are reported. Cyt c-PAA conjugates were prepared by carbodiimide coupling. PAA with molecular weight (Mw) ranging from 1.8k to 250k g mol-1 were employed, and the effect of PAA Mw on peroxiodase kinetics was assessed. The kcat value increased with increased Mw of PAA, ranging from 0.077(±0.002) s-1 in the absence of PAA to 2.66(±0.08) s-1 for the conjugate of cyt c with 250k PAA. Enzymatic activity studies over pH 6-8 indicated improved activity for cyt c-PAA conjugates at neutral or slightly alkaline pH. Examination of the cyt c heme spectroscopy in the presence of H2O2 revealed that formation of compound III, a reactive intermediate that leads to enzyme inactivation, was supressed in cyt c-PAA conjugates. Thus, we suggest the kcat enhancement can be attributed to acidification of the pH microenvironment and inhibition of the formation of a reactive intermediate that deactivates cyt c during the catalytic cycle.
Synthesis of copper ion incorporated horseradish peroxidase-based hybrid nanoflowers for enhanced catalytic activity and stability
Somturk, Burcu,Hancer, Mehmet,Ocsoy, Ismail,?zdemir, Nalan
, p. 13845 - 13852 (2015)
In this study, we report the preparation, catalytic activity and stability of a hybrid nanoflower (hNF) formed from horseradish peroxidase (HRP) enzyme and copper ions (Cu2+). We studied the morphology of hNFs as a function of the concentrations of copper (Cu2+) ions, chloride ions (Cl-) and HRP enzyme, the pH of the buffer solution (phosphate buffered saline), and the temperature of the reaction. The effects of morphology on the catalytic activity and stability of hNFs were evaluated by oxidation of guaiacol (2-methoxyphenol) to colored 3,3-dimethoxy-4,4-diphenoquinone in the presence of hydrogen peroxide (H2O2). The enhanced activity of hNFs synthesized (from 0.02 mg mL-1 HRP in 10 mM PBS (pH 7.4) at +4°C) was 17595 U mg-1, which was ～300% higher than free HRP in PBS, where it achieved an activity of 5952 U mg-1. In terms of stability, these hNFs stored in PBS buffer at +4°C and room temperature (RT = 20°C) lost 4% and 20%, respectively, of their initial catalytic activities within 30 days. Finally, we demonstrated that these hNFs can be utilized as sensors for the detection of dopamine.
