Surface-Enhanced Raman Spectroscopic Analysis of Flavoenzyme Cofactors: Guidance for Flavin-Related Bio- and Chemo- Sensors

• Published in: Chemosensors Vol. 11; no. 3; p. 190
• Main Authors: Liu, Yawen, Ma, Hao, Zhao, Junqi, Wang, Jihong, Han, Xiaoxia, Zhao, Bing
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.03.2023
• Subjects: Adenine; Adenosine; Adsorption; Analysis; Aqueous solutions; Cancer; Chemotherapy; Chromophores; Cofactors; Electron transport; Enzymes; Feasibility studies; Flavin; flavin adenine nucleotide; flavin mononucleotide; Flavin-adenine dinucleotide; isoalloxazine; Lasers; Microscopy; Nanoparticles; Nucleotides; Raman spectroscopy; riboflavin; Sensors; Silver; Spectrum analysis; Structural analysis; Surface chemistry; surface-enhanced Raman spectroscopy; Vitamin B; China; Beijing China
• ISSN: 2227-9040; 2227-9040
• DOI: 10.3390/chemosensors11030190

Flavin mononucleotides (FMNs) and flavin adenine nucleotide (FAD) play vital roles in the electron-transfer processes in diverse enzymatic reactions. Owing to the isoalloxazine chromophore, flavins are easily detectable by surface-enhanced Raman spectroscopy (SERS), a surface-sensitive technique. However, the details of the adsorption of flavins on SERS-active materials have never been investigated. In this study, a comprehensive SERS analysis of flavins containing lumichrome and lumiflavin on silver nanoparticles was conducted. With the aid of density-functional-theory calculations, our results suggested that the flavin molecules were adsorbed on the silver nanoparticles via the N3 site of the isoalloxazine moiety, which had a stronger adsorption ability than the adenine moiety in the FAD. The SERS spectra of the flavins at different pH values also supported this conclusion. This study demonstrated the feasibility of SERS for the structural characterization of flavins, paving the way for the functional exploration of flavin-labeled detection sensors and flavoprotein researches.