Reconstitution of the quinoprotein glucose dehydrogenase from its apoenzyme on a gold electrode surface modified with a monolayer of pyrroloquinoline q

Katz, Eugenii; Schlereth, Daniela D.; Schmidt, Hanns‐Ludwig; Olsthoorn, Arjen J. J.

doi:10.1016/0022-0728(93)03094-6

Cited by 86 publications

(31 citation statements)

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“…Thus, especially for large proteins, the overall ET distance can only be decreased by attempting an anisotropic orientation of the protein prior to covalent immobilisation with the active site exposed towards the electrode surface. Examples of this strategy are the reconstitution of holo oxidases with thiolderivatised FAD, [24±26] of PQQ-dependent dehydrogenases with PQQ-modified thiol monolayers [27] and of myoglobin by means of monolayers of thiol-derivatised hemin. [28] In this paper, we report the design and evaluation of an electrode architecture for orientated immobilisation of HRP on a SAM; this procedure circumvents tedious syntheses of cofactor-derivatised thiol compounds that possess the appropriate spacer length, while the flexibility to adapt the distances to the specific needs of envisaged direct ET processes is maintained.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Orientation of Horseradish Peroxidase by Reconstitution on a Thiol-Modified Gold Electrode

et al. 2000

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Horseradish peroxidase (HRP) was reconstituted on the surface of a gold electrode that was modified first with a hemin-carbon-chain-thiol derivative followed by addition of the apo protein to the contacting solution. To facilitate the reconstitution of the holo enzyme, the hemin needs to be immobilised on a carbon-chain spacer arm. To achieve this, an immobilisation protocol was developed that is based on the initial formation of a mixed self-assembled monolayer on the gold surface consisting of 3-carboxypropyl disulphide and an activated disulphide (3,3'-dithiodipropionic acid di-(N-succinimidyl ester)) followed by binding of a diaminoalkane to the activated disulphide. The hemin was then coupled to the second amino group of the diaminoalkane by means of a carbodiimide coupling reagent. Finally, the enzyme was reconstituted on the hemin-modified surface by immersion of the electrode in a solution containing apo-HRP. The advantage of this method is that the length of the spacer arm can be changed easily, because diaminoalkanes of different chain lengths are available. The electrochemistry of the hemin and the reconstituted HRP electrodes was studied by means of cyclic voltammetry and differential-pulse voltammetry. The catalytic ability for reduction of hydrogen peroxide was investigated for both direct and mediated electrochemistry with a soluble electron donor (ortho-phenylenediamine).

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Section: Introductionmentioning

confidence: 99%

Anisotropic Orientation of Horseradish Peroxidase by Reconstitution on a Thiol-Modified Gold Electrode

et al. 2000

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“…7 Improper orientation of PQQ could affect its reversible oxidation process. Kanninen et al 8 reported the physical adsorption of PQQ to single-walled and few-walled carbon nanotube (FWCNT)-modified glassy carbon electrodes.…”

Section: H3098mentioning

confidence: 99%

“…6,7 These studies can be challenging due to the pH dependence of the redox potentials. 6,8,9 Using a cystamine-monolayer Au-modified electrode, Katz et al…”

mentioning

confidence: 99%

“…5 The electrochemistry of PQQ has been studied quite extensively in both solution and immobilized forms via cyclic voltammetry (CV) and potentiometric titration studies. 6,7 These studies can be challenging due to the pH dependence of the redox potentials. 6,8,9 Using a cystamine-monolayer Au-modified electrode, Katz et al 6 studied the electrochemistry of PQQ in solution using CV and reported the change in potential with pH to be about 60 mV pH −1 at pH < 6.2; 30 mV pH −1 at 6.2 < pH < 8.6; and about 60 mV pH −1 at pH > 8.…”

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confidence: 99%

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Electrochemistry of Pyrroloquinoline Quinone (PQQ) on Multi-Walled Carbon Nanotube-Modified Glassy Carbon Electrodes in Biological Buffers

Emahi

Mitchell

Baum

2017

J. Electrochem. Soc.

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Pyrroloquinoline quinone (PQQ) is an important electrocatalyst and redox cofactor for many enzymes used in bioanalytical applications. Careful selection of electrode modifications and buffer compositions is required due to PQQ's tendency to be irreversibly reduced on bare electrodes and the strong effect of pH on its electrochemistry. Multi-walled carbon nanotubes (MWCNTs) can effectively modify glassy carbon electrodes, but PQQ's behavior at these surfaces has not been investigated. While phosphate buffers have been used extensively to characterize PQQ's electrochemistry, phosphate buffers can act as chelating agents for important metal ions needed by PQQ and biomolecules. Different physiological buffers could overcome these challenges and expand the buffer options for biofuel cells. Using cyclic voltammetry, we studied PQQ in HEPES, MOPS, TRIS, and phosphate buffers at pH 7 with MWCNT-modified electrodes. While there were no significant differences in PQQ's behavior with the various buffers, the ionic composition of the non-phosphate buffers was very important. We observed that K + and Mg 2+ were the most influential ions for the reversible reduction-oxidation of PQQ. PQQ's electrochemistry was also affected by the length of and the functional groups on the MWCNTs, indicating that the electron transfer kinetics were quite sensitive to the surface chemistry of the electrodes. Pyrroloquinoline quinone (PQQ) is a redox cofactor found in the active sites of a number of enzymes. Most of these quinoproteins are dehydrogenases capable of catalyzing the oxidation of a broad range of substrates, such as alcohols, acids, aldehydes and sugars. 1 PQQ-dependent glucose dehydrogenase, for example, is capable of oxidizing several mono-and disaccharides, including glucose, maltose, lactose, galactose, xylose and mannose.1 The uniqueness of the quinoproteins and their broad substrate specificities have led to their use in bioanalytical applications, including biosensors and biofuel cells.In the absence of an enzyme, PQQ itself is capable of catalyzing redox reactions, including the oxidation of thiols, 2,3 amino acids, 4 and the redox cofactor nicotinamide adenine dinucleotide (NAD + ). 5The electrochemistry of PQQ has been studied quite extensively in both solution and immobilized forms via cyclic voltammetry (CV) and potentiometric titration studies. 6,7 These studies can be challenging due to the pH dependence of the redox potentials. 6,8,9 Using a cystamine-monolayer Au-modified electrode, Katz et al.6 studied the electrochemistry of PQQ in solution using CV and reported the change in potential with pH to be about 60 mV pH −1 at pH < 6.2; 30 mV pH −1 at 6.2 < pH < 8.6; and about 60 mV pH −1 at pH > 8.6. In another study using PQQ immobilized on few-walled carbon nanotube (FWCNT)-modified glassy carbon electrodes, the change in PQQ's redox potential was estimated to be approximately 67 mV pH −1 , with the highest reversible reduction-oxidation observed at ∼pH 2. The nature of the modified electrode surface can also affect P...

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“…The CFE can also be modified by using the gold mask in combination with selfassembly [63][64][65][66][67][68] to produce an enzyme modification located on the gold mask itself, a positive mask. After deposition of a gold mask, an aminated surface is prepared by immersing the CFE with mask in an aqueous 20 mM solution of cystamine for 2 h. The gold surface is cleaned prior to the deposition by immersing the electrode in concentrated KOH for 1 h, concentrated H2SO4 for 12 h, and then concentrated HNO3 for 15 min.…”

Section: Positive Gold-mask Modificationmentioning

confidence: 99%

Fabricating and Imaging Carbon-Fiber Immobilized Enzyme Ultramicroelectrodes with Scanning Electrochemical Microscopy

Tenent

Wipf

2001

ANAL. SCI.

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The scanning electrochemical microscope (SECM) is used to image the activity of enzymes immobilized on the surfaces of disk-shaped carbon-fiber electrodes. SECM was used to map the concentration of enzymatically produced hydroquinone or hydrogen peroxide at the surface of a 33-µm diameter disk-shaped carbon-fiber electrode modified by an immobilized glucose-oxidase layer. Sub-monolayer coverage of the enzyme at the electrode surface could be detected with micrometer resolution. The SECM was also employed as a surface modification tool to produce microscopic regions of enzyme activity by using a variety of methods. One method is a gold-masking process in which microscopic gold patterns act as mask for producing patterns of chemical modification. The gold masks allow operation in both a positive or negative process for patterning enzyme activity. A second method uses the direct mode of the SECM to produce covalently attached amine groups on the carbon surface. The amine groups are anchors for attachment of glucose oxidase by use of a biotin/avidin process. The effect of non-uniform enzyme activity was investigated by using the SECM tip to temporarily damage an immobilized enzyme surface. SECM imaging can observe the spatial extent and time-course of the enzyme recovery process.

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Reconstitution of the quinoprotein glucose dehydrogenase from its apoenzyme on a gold electrode surface modified with a monolayer of pyrroloquinoline q

Cited by 86 publications

References 17 publications

Anisotropic Orientation of Horseradish Peroxidase by Reconstitution on a Thiol-Modified Gold Electrode

Anisotropic Orientation of Horseradish Peroxidase by Reconstitution on a Thiol-Modified Gold Electrode

Electrochemistry of Pyrroloquinoline Quinone (PQQ) on Multi-Walled Carbon Nanotube-Modified Glassy Carbon Electrodes in Biological Buffers

Fabricating and Imaging Carbon-Fiber Immobilized Enzyme Ultramicroelectrodes with Scanning Electrochemical Microscopy

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