Catalytic and Inhibitory Kinetic Behavior of Horseradish Peroxidase on the Electrode Surface

Abstract

Enzymatic biosensors are often used to detect trace levels of some specific substance. An alternative methodology is applied for enzymatic assays, in which the electrocatalytic kinetic behavior of enzymes is monitored by measuring the faradaic current for a variety of substrate and inhibitor concentrations. Here we examine a steady-state and pre-steady-state reduction of H2O2 on the horseradish peroxidase electrode. The results indicate the substrate-concentration dependence of the steady-state current strictly obeys Michaelis-Menten kinetics rules; in other cases there is ambiguity, whereby he inhibitor-concentration dependence of the steady-state current has a discontinuity under moderate concentration conditions. For pre-steady-state phases, both catalysis and inhibition show an abrupt change of the output current. These anomalous phenomena are universal and there might be an underlying biochemical or electrochemical rationale.

Integrated Experimental and Theoretical Studies on an Electrochemical Immunosensor

“…Previous mathematical models developed to describe kinetics of HRP on the electrodes [ 21 , 37 , 38 , 39 , 40 ] focused on the enzyme’s kinetics or were based on an assumption that the J is mass-transfer limited. In contrast, our model explicitly calculates the rates of all key reaction and mass transfer steps, all of which could limit the signal’s magnitude to some extent.…”

“…The non-linear, ping-pong kinetic mechanism describing HRP oxidation of C in the presence of is shown in Reactions (i)–(iii) [ 33 , 34 , 35 , 36 ]: HRP (Fe 3+ ) + H 2 O 2 → Compound(I) + H 2 O Compound (I) + C → Compound (II) + Q Compound (II) + C → HRP (Fe 3+ ) + Q where compounds (I) and (II) are oxidized intermediates of HRP. The kinetic formula resulting from this mechanism [ 21 , 37 , 38 , 39 , 40 ] is: where is the reaction rate, is the maximum reaction rate constant ( , and [HRP] are turnover number and HRP concentration within the immunosensing layer, respectively; and are the corresponding Michaelis–Menten constants, and and are and C concentrations, respectively.…”

Cystatin C biosensors for diagnosis of kidney failure – A literature review

“…When the proteins used as bioreceptors are antibodies or antigens, they can be further categorized as immunosensors [38,39] . Moreover, when the biorecognition element is DNA, these biosensors are usually called genosensors [40] and enzymatic sensors are those that use the activity of enzymes as detection elements [41].…”