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Supporting Information
Incorporating ATP into Biomimetic Catalysts for Realising Exceptional
Enzymatic Performance over a Broad Temperature Range
Scheme S1. Scheme describing the main shortcomings and challenges of present
peroxidase mimics.
Table S1. Comparison of the kinetic parameters of the Au-SiO2 catalyst and HRP
enzyme. [E] is the concentration of Au-SiO2 catalyst (based on the concentration of
AuNPs) or enzyme, Km is the Michaelis constant, Vmax is the maximum reaction
velocity, and Kcat is the catalytic constant, where Kcat=Vmax/[E].
Catalyst
Substance
Km [mmol/L]
Vmax [μmol·l-1·s-1]
Kcat [s-1]
Au-SiO2 (41.2 nM) [1]
H2O2
119.2±2.24 [a]
0.05258±0.00207
1.276±0.050[a]
HRP (0.025 nM) [1]
H2O2
0.226±0.011[a]
0.01689±0.00062
675.6±24.8[a]
[a] The Km value of Au-SiO2 is higher than that of HRP, and the Kcat value of Au-SiO2
is lower than that of HRP. These results imply that the Au-SiO2 catalyst has low
catalytic activity and binding affinity compared with the natural enzyme HRP.
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Figure S1. (a, b) TEM images of the Au-SiO2 nanoparticles under different
magnifications.
Figure S2. Size distribution histogram of AuNPs in the Au-SiO2 catalyst. The total
number of clusters counted for the historgram was 100.
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Figure S3. Formation of the coloured ABTS product due to the oxidation of ABTS is
pH-dependent, and the optimum activity occurs at pH 4.0. ([ABTS] = 1 mM, [H2O2]
= 50 mM, [Au-SiO2 nanoparticles] = 250 μg ml-1)
Figure S4. Comparison of the stability of Au-SiO2 nanoparticles and HRP at different
pH values (from 1 to 9). Both catalysts were first incubated for 2 h at a range of pH
values, and then, the catalytic activities were measured under the same conditions.
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Figure S5. The effects of operating temperature on the activity of the natural enzyme
HRP. ([ABTS] = 1 mM, [H2O2] = 4 mM, [HRP] = 1 ng ml-1)
Figure S6. ATP concentration-dependent change in the absorption signal of the
reaction solution at 417 nm.
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Figure S7. Time-dependent absorbance changes at 417 nm as a result of the catalysed
oxidation of ABTS at 85 °C: (black) absorption changes in the absence of ATP; (red)
absorption changes after the addition of 2.5 mM ATP.
Figure S8. a) Structures of TMB and its one-electron oxidation product oxTMB. b)
Temperature-dependent catalytic activities of Au-SiO2 catalyst using TMB as a
substrate in the absence or presence of 2.5 mM ATP.
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Figure S9. Effects of typical nucleotides (2.5 mM) on an Au-SiO2-mediated
ABTS-H2O2 system. All experiments were performed at high temperature (75 °C, 10
min).
Figure S10. Stability of ABTS•+ in the presence of glutathione, ascorbic acid or
ATP-γ-S.
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Figure S11. The activity of ATP or ATP/catalyst complex incubated in a reaction
solution including H2O2 and ABTS. (Demonstration that the enhancement activity
does not result from ATP alone).
Figure S12. EPR spectra of ABTS•+ under different conditions: (1) control; (2) 50
mM H2O2, 85 °C; (3) 50 mM H2O2 and 2.5 mM ATP, 85 °C.
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Figure S13. (a) Absorption spectra in the absence or presence of free phosphate after
mixing with malachite green and ammonium molybdate. (b) The free-phosphate
production from the hydrolysis of ATP at different temperatures.
Figure S14. The stability of graphene oxide, citrate-capped AuNPs, graphene-haemin
and graphene-AuNP nanocomposites in the presence of 2.5 mM ATP and 20% ionic
liquid (choline dihydrogen phosphate).
[1] Lin, Y., Li, Z., Chen, Z., Ren, J. & Qu, X. Mesoporous silica-encapsulated gold
nanoparticles as artificial enzymes for self-activated cascade catalysis. Biomaterials
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34, 2600-2610 (2013).
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