Fluorescent Derivatization of Xanthurenic Acid and Nicotinic Acid with Horseradish Peroxidase in the Presence of Excess Hydrogen Peroxide

Abstract

The fluorescent derivatization of tryptophan metabolites (xanthurenic acid, nicotinic acid, picolinic acid, and 3-hydroxyanthranilic acid) by the catalytic activity of horseradish peroxidase (HRP) was investigated in the presence of excess H2O2. Non-fluorescent xanthurenic acid (XA) and nicotinic acid (NA) were converted into a fluorescent compound with maximum excitation and emission wavelengths at 325 and 425 nm, and 318 and 380 nm, respectively. This fluorescent derivatization was developed for the fluorometric determination of trace amounts of XA and NA. The calibration curves were linear from 1.0 to 10.0 nmol XA and from 5.0 to 20.0 nmol NA in a 1.0-mL sample solution. The UV spectra of the reaction solutions suggested that compound III as an intermediate of HRP played an essential role in this fluorescent derivatization with HRP.

Encapsulated Hydrogels by E-beam Lithography and Their Use in Enzyme Cascade Reactions

“…Enzyme activity was then confirmed through an enzyme cascade reaction between HRP and GOX. When hydrogen peroxide is present, HRP can modify numerous substrates in solution , including fluorescent substrates − and Amplex Red. This reporter molecule may be used to quantify enzymatic activity or hydrogen peroxide concentration .…”

Fluorescent Derivatization of Aromatic Carboxylic Acids with Horseradish Peroxidase in the Presence of Excess Hydrogen Peroxide

“…1), all of which are aromatic carboxylic acids, are converted fluorescent compounds by the catalytic activity of HRP in the presence of excess H2O2. [4][5][6] In this study, we further investigated the action of HRP in the presence of excess H2O2 on various aromatic carboxylic acids shown in Fig. 1 to determine whether such activity, as previously demonstrated, would yield fluorescent compounds.…”

“…Previously, we demonstrated that non-fluorescent tryptophan metabolites, such as nicotinic acid (1b), quinolinic acid (2a), kynurenic acid (8a), and xanthurenic acid (8b), were converted into fluorescent compounds by the catalytic activity of HRP in the presence of excess H2O2. [4][5][6] So, the fluorescent derivatization of various non-or weakly fluorescent aromatic carboxylic acids in Fig. 1 was investigated in the presence of excess H2O2.…”

Determinación de cis-/trans-Estilbenos (Resveratrol y Piceido), Triptófano y Metabolitos en productos apícolas por cromatografía de líquidos

“…En el caso de la detección por fluorescencia, usualmente se añade acetato de zinc en post-columna para mejorar la señal [187][188][189][190] , aunque en otro método se empleó la detección de fluorescencia inducida por láser [191] . El KYNA también ha sido analizado directamente por espectrofluorimetría previa derivatización con peroxidasa de rábano (HRP) en presencia de peróxido de hidrógeno [192][193][194] , o por reacción fotoquímica post-columna con peróxido de hidrógeno [195] . También se ha determinado KYNA por detección UV [196,197] , o espectrofotometría después de la derivación con ácido sulfanílico diazotizado [198] , y con menor frecuencia usando NMR [199] , o la espectrometría de masas [77,[200][201][202] .…”

“…Dada la falta de estudios sobre la determinación simultánea de estos compuestos en miel, y que la mayoría de los trabajos se realizan en matrices biológicas [77,[187][188][189][190][191][192][193][194][195][196][197][198][199][200][201][202][203] , se ha desarrollado un método de cromatografía de líquidos con detección de diodos…”