Unexplored interactions between pyrroloquinoline quinone and β-nicotinamide adenine dinucleotide

Hsi Jung Jao, Pei Yi Tsai, Chong Mou Wang

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8 Citations (Scopus)

Abstract

The interactions between pyrroloquinoline quinone (PQQ) and β-nicotinamide adenine dinucleotide (NAD(H)) characterized by spectral and voltammetric means are reported in this paper. PQQ exists with six major acid-base derivatives in aqueous solutions; the derivative predominating at pH 3, denoted H2Q-, was characterized to be responsible for the electrochemical and photochemical activities of PQQ, such as for the photooxidation of NADH. In contrast, the derivatives predominating at pH > 5, such as HQ2- and Q3-, are responsible for the interaction with NAD+; the equilibrium constant was estimated to be ∼106. Although the basic derivatives are less active in emission compared to H2Q-, incorporating NAD+ can enhance their activity in this respect. The titrations of NAD+ with HQ2- and Q3- confirm the complexation reactivity of PQQ to NAD+, and suggest that the reaction sites of PQQ for NAD+ are the same as for Ca2+ ions. Thanks to those unique properties, PQQ can photochemically sense glucose and ethanol as NAD+ and the respective dehydrogenases are incorporated.

Original languageEnglish
Pages (from-to)141-149
Number of pages9
JournalJournal of Electroanalytical Chemistry
Volume606
Issue number2
DOIs
Publication statusPublished - 2007 Aug 15

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Keywords

  • Biosensing
  • Pyrroloquinoline quinone
  • β-Nicotinamide adenine dinucleotide

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry

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