Expanding PQQ's Biosensor Applications: the Effects of Illumination on the Reactivity of PQQ.

Abstract

2,7,9-Tricarboxyl-1H-pyrrolo[2,3-f]quinoline-4,5-dione, commonly known as PQQ or pyrroloquinoline quinone, functions as a cofactor in bacterial methanol and glucose dehydrogenases.This study focuses on PQQ found within the homodimeric enzyme soluble glucose dehydrogenase (sGDH) of bacterium Acinetobactor calcoaceticus .Within sGDH, PQQ oxidizes glucose to D-glucono-lactone.Glucose is hence a natural substrate of PQQ. As PQQ is structurally similar to photochemically reactive phenanthrene-9,10-dione, we expect that light can be used as a tool to alter PQQ's reactivity.Thus far, we have found that under illumination, PQQ shows enhanced reactivity with ketose sugar D-fructose.This is significant since ketoses are not among PQQ's natural substrates.Our aim is to isolate and characterize the product of this light reaction.By studying PQQ's reactivity under illumination, we aim to broaden its substrate specificity and thus expand its biosensor applications.