Nitroxide-Modified Protein-Incorporated Nanoflowers with Dual Enzyme-Like Activities

Figures & data

Scheme 1 Synthesis of polynitroxylated human serum albumin-incorporated nanoflowers.

Figure 1 H₂O₂ depletion catalyzed by PNA-incorporated nanoflowers.

Figure 2 O₂ evolution catalyzed by PNA-incorporated nanoflowers.

Table 1 The Specific Activity of the PNA-Incorporated Nanoflowers

Nanoflower	Specific Activity (μmol/min/mg)
PNA-nano-A	1004.02 ± 34.32
PNA-nano-B	1782.03 ± 37.60
PNA-nano-C	584.01 ± 29.88
PNA-nano-D	164.00 ± 32.45

Figure 3 The effect of PNA on the amount of nitroxide encapsulated into the nanoflowers.

Figure 4 SEM images of the PNA-nano-A (A–D), PNA-nano-B (E–H), PNA-nano-C (I–L), and PNA-nano-D (M–P) samples.

Figure 5 FTIR spectra of Cu₃(PO₄)₂ crystal without PNA (A), the PNA-incorporated nanoflowers (B), and PNA (C).

Figure 6 EPR spectra of PNA (A) and PNA-incorporated nanoflowers (B).

Table 2 Comparison of Kinetic Parameters Between PNA-Incorporated Nanoflowers and Native Catalase

Catalysts	Km (mM)	Vmax (μmol/min/mg)	Kcat (S^−1)	Kcat/Km (M^−1S^−1)
PNA-incorporated nanoflowers	17.41	0.44 × 10^4	3.78 × 10^4	0.21 × 10^7
Catalase from bovine liver^Citation29	28.60	1.43 × 10^5	60.06 × 10^4	2.10 × 10^7

Figure 7 Steady-state kinetic assay of the PNA-incorporated nanoflowers. Velocity indicates the rate of H₂O₂ depletion.

Figure 8 Steady-state kinetic assay of the PNA-incorporated nanoflowers. Velocity  indicates the rate of O₂ evolution.

Figure 9 Lineweaver–Burk plots of the reaction velocity of the PNA-incorporated nanoflowers as a function of H₂O₂ concentration ranging from 3 to 60 mM. V indicates the rate of H₂O₂ depletion.

Figure 10 Lineweaver–Burk plots of the reaction velocity of the PNA-incorporated nanoflowers as a function of H₂O₂ concentration ranging from 3 to 60 mM. V indicates the rate of O₂ evolution.

Figure 11 O₂ evolution catalyzed by native catalase (1), PNA-incorporated nanoflowers (2), and HSA-incorporated nanoflowers (3). For each reaction condition, the amounts of sample used for the assay were: 10 μL native catalase (0.001 mg/mL), 50 μL PNA-incorporated nanoflowers (0.01 mg/mL), and 50 μL HSA-incorporated nanoflowers (0.01 mg/mL). One unit of activity is defined as the evolution of 1 μmol/min of oxygen at 25°C in deionized water.

Figure 12 The catalytic mechanism of PNA-incorporated nanoflowers with dual enzyme-like activities.

Figure 13 Reuse of PNA-incorporated nanoflowers.

Tukel SS, Alptekin O. Immobilization and kinetics of catalase onto magnesium silicate. Process Biochem. 2004;39(12):2149–2155. doi:10.1016/j.procbio.2003.11.010

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