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Updated: Jul 18, 2026

Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate
Published on: April 6, 2022
Photo-induced processes in vitamin B6 compounds
Bartolomé Vilanova1, Miquel Adrover, Francisco Muñoz
1Institut Universitari d'Investigació en Ciències de la Salut, Departament de Química, Universitat de les Illes Balears, E-07122 Palma de Mallorca.
Multi-wavelength stopped-flow spectroscopy (MSFS) reveals that light can alter vitamin B6 compounds, affecting chemical equilibria. This photo-induced process is crucial for accurate enzyme studies using MSFS.
Area of Science:
- Biochemistry
- Spectroscopy
- Photochemistry
Background:
- Vitamin B6 compounds exist in various tautomeric or hydrated forms.
- Schiff bases are formed between vitamin B6 vitamers and amino acids.
- Photosensitivity of some vitamin B6 compounds can influence experimental outcomes.
Purpose of the Study:
- To investigate chemical equilibria of vitamin B6 compounds and their Schiff bases using MSFS.
- To analyze potential photo-induced processes during spectroscopic analysis.
- To determine the impact of light irradiation on tautomeric composition.
Main Methods:
- Multi-wavelength stopped-flow spectroscopy (MSFS) applied at 25°C and variable pH.
- Analysis of electronic absorption spectra using log-normal curves.
- Continuous irradiation (200-700 nm) with a 75-W Xe lamp.
Main Results:
- Continuous irradiation displaced chemical equilibria in pyridoxamine and pyridoxal 5'-phosphate.
- The Schiff base of epsilon-aminocaproic acid with pyridoxal 5'-phosphate showed no sensitivity to irradiation.
- Photo-induced processes were detected in specific vitamin B6 compounds under irradiation.
Conclusions:
- Photo-induced processes in pyridoxamine and pyridoxal 5'-phosphate must be considered during MSFS analysis.
- These findings are critical for studying vitamin B6-dependent enzymes using MSFS when free vitamers are present.
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