The use of artificial solid-state pores for measurement of catalytic activity of individual molecules of horseradish peroxidase

Aim. Determination of the catalytic activity of a single molecule of horseradish peroxidase (HRP) in the oxidation reaction of the substrate 2,2ʹ-azino-bis-[3-ethylbenzthiazoline-6- sulfonate] (ABTS) with hydrogen peroxide.

Methodology. To determine (monitor) the catalytic activity of HRP, pore technology has been used; it has allowed us to analyze the activity of a single HRP molecule without introducing additional components into the system to enhance the signal. For this purpose, a solid-state pore of about 5 nm in size, formed by electron-beam drilling in a silicon nitride plate of ~40 nm thickness, has been used. A HRP molecule has been embedded in this pore, after which the catalytic activity of the molecule embedded in the pore in the presence of ABTS and H₂O₂ has been analyzed by measuring the ion current through the pore with the HRP molecule embedded in it.

Results. A pore detector has been proposed to study the catalytic activity of HRP in the reaction of ABTS oxidation. It has been found that this detector made it possible to monitor the activity of this enzyme by registering of ion current through the pore.

Research implications. It has been shown that the manufactured pore can be used to monitor HRP activity. The results obtained are important for the development of work in the field of enzyme research at the level of single molecules.

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