Thermostable Peroxidase−Polylysine Films for Biocatalysis at 90 °C

Abstract

Cross-linked films of poly(l-lysine) (PLL) and enzymes covalently linked to surfaces provided remarkable thermostability, enabling biocatalysis at 90 degrees C. Soret spectra, circular dichroism, and voltammetry showed that PLL films containing peroxidases or myoglobin were stable for up to 9 h at 90 degrees C, while the same enzymes in solution denatured completely within 20 min. Biocatalytic reduction of t-BuOOH with enzyme-PLL films, using rotating disk voltammetry, provided Michaelis kcat/Km values. Results showed that horseradish peroxidase (HRP)-PLL is 3-fold more active than soybean peroxidase (SBP)-PLL at 25 degrees C, but SBP-PLL is slightly more active at 90 degrees C. SBP-PLL films had 8-fold larger kcat/Km values at 90 degrees C compared to 25 degrees C. Oxidation of o-methoxyphenol to 3,3'-dimethoxy-4,4'-biphenoquinone by peroxidase-PLL-coated silica colloids gave better yields at 90 degrees C than 25 degrees C, suggesting increasing catalytic efficiency and selectivity at the higher temperature. These biocolloids were reusable with little loss of activity at 90 degrees C.

Electrochemical Characterization of Myoglobin‐Polylysine Films at a Temperature Range of 6–80 °C

“…But from 23 to 80 8C, the E8' shifts are quite small. The observation made at higher temperatures is consistent with our previous work [11] where the E8' remained constant from 25 8C to 908C for this myoglobinpolylysine films. Overall, the E8' obtained with this myoglobin cross-linked in the polylysine films (figure 6) is different from those observed with same myoglobin in solution.…”

“…Similar trends in surface concentrations as a function of temperature were reported previously at temperature range of 25 8C -90 8C [11]. Data in figure 4 exhibit similar trend to that of electrochemical currents obtained in Figure 3.…”

Technologies for Continuous Glucose Monitoring: Current Problems and Future Promises

“…Reports have begun to emerge on nanotechnology-based venues to reduce natural enzyme denaturation. [173][174][175][176] For example, the catalytic activity of an enzyme has been shown to be preserved when immobilized on nanostructured supports such as zeolites and phosphates. These are promising strategies that could be applied to prolong the lifetime of CGM devices.…”

Hydrogen peroxide biosensor based on direct electrochemistry of soybean peroxidase immobilized on single-walled carbon nanohorn modified electrode

“…Noteworthily, SBP is less susceptible to heme loss and permanent inactivation by hydrogen peroxide than HRP (McEldoon and Dordick, 1996;Henriksen et al, 2001;Kamal and Behere, 2002;Ryan et al, 2006). It can maintain its bioactivity over a wide pH range (3-10), at high temperature (<70 • C), and in a variety of organic solvents (McEldoon et al, 1995;Kamal and Behere, 2002;Guto et al, 2007). Furthermore, SBP is more economical for practical applications because it can be obtained readily from cheap soybean seed coats.…”