The Intrinsic Enzyme Activities of the Classic Polyoxometalates

Abstract

The mimicking enzyme activities of eighteen classic POMs with different structures, Keggin (H3PW12O40, H4SiW12O40, H4GeW12O40, K4GeW12O40, H3PMo12O40, H4SiMo12O40 and Eu3PMo12O40), Wells-Dawson (H6P2Mo18O62, α-(NH4)6P2W18O62 and α-K6P2W18O62·14H2O), lacunary-Keggin (Na8H[α-PW9O34], Na10[α-SiW9O34], Na10[α-GeW9O34] and K8[γ-SiW10O36]), the transition-metal substituted-type (α-1,2,3-K6H[SiW9V3O34] and H5PMo10V2O40), sandwich-type (K10P2W18Fe4(H2O)2O68) and an isopolyoxotungstate (Na10H2W12O42) were screened and compared. The mechanisms and reaction conditions of POMs with mimicking enzyme-like activities were also analyzed. The results shown that the structures, the hybrid atoms, the coordination atoms, the substituted metal atoms, pH and substrate are the effect factors for the enzyme mimic activities of POM. Among the eighteen POMs, H3PW12O40, H4SiW12O40, H4GeW12O40, α-(NH4)6P2W18O62, α-K6P2W18O62·14H2O, Na8H[α-PW9O34], Na10[α-SiW9O34], Na10[α-GeW9O34], K8[γ-SiW10O36], K10P2W18Fe4(H2O)2O68 and Na10H2W12O42 had the peroxidase activities. Eu3PMo12O40, H3PMo12O40, H4SiMo12O40, α-1,2,3-K6H [SiW9V3O34], H6P2Mo18O62 and H5PMo10V2O40 showed the oxidase-like activities. K4GeW12O40 did not show the peroxidase and oxidase activities. The Na8H[α-PW9O34], Na10[α-SiW9O34] and Na10[α-GeW9O34] showed intrinsic enzyme activities at alkaline conditions, which were different from other type of POMs. The sandwich-type K10P2W18Fe4(H2O)2O68 displayed the strongest peroxidase activity, which is similar to natural horseradish peroxidase.

Vanadium‐Substituted Tungstosulfate Polyoxometalates as Peroxidase Mimetics and Their Potential Application in Biosensing

“…The level of K m and V max obtained for SVW 11 and SV 2 W 10 are highly comparable to pervious findings of various nanostructured materials based nanozymes as shown in (Table 1). [10,14,23,24,[33][34][35][36][37][38][39][40] These results suggest that the POMs exhibit strong affinity towards H 2 O 2 and TMB and possess excellent peroxidase-like activity. A separate set of experiments were set up to compare the catalytic performance of these novel of POMs with standard natural peroxidase horseradish peroxidase (HRP).…”

“…POMs have found wide ranging applications in the area of catalysis. [12,14] Additionally, the POMs can be systematically tuned at atomic levels: [15] Removal of one, two or three metal octahedrons from the parent POMs, [XM 12 O 40 ] nÀ (X=S, P, As, Si, Ge; M=W, Mo) by sophisticated pH control results in the formation of mono-, dior tri-lacunary POMs. [16] POM catalysts have many advantages, such as high efficacy, stability and designability, making them promising candidates for industrial catalysts.…”

“…[17,23] Among various classes of POMs, it has been reported that Keggin-structured POMs exhibit highest nanozyme activity compared to Wells-Dawson and lacunary type POMs. [14] However, so far only a handful of research articles have explored the peroxidase mimicking activities of H 4 [SiW 12 O 40 ], [17] [PCoW 11 O 39 ] 5À , [23] and POM-Calix hybrid. [24] In this research work, peroxidase-like activity of two 11 and SV 2 W 10 were found to possess peroxidase-like activities.…”

AuNPs@PMo12nanozyme: highly oxidase mimetic activity for sensitive and specific colorimetric detection of acetaminophen

“…[20][21][22] Thus, POMs can be applied as enzyme mimics to catalyse H 2 O 2based oxidation of 3,3 0 ,5,5 0 -tetramethylbenzidine (TMB). 23 Li et al prepared three tetra-nuclear ZrIV-substituted POMs, which exhibit peroxidase-like activities. 24 It was found that most of the POMs are stable and have more enzyme activities at low pH values (about 3.0 or 4.0).…”

“…24 It was found that most of the POMs are stable and have more enzyme activities at low pH values (about 3.0 or 4.0). 23,24 However, it is interesting to develop intrinsic oxidase nanozymes since they do not use harmful H 2 O 2 as a co-substrate.…”