Development of Simultaneous Enzymatic Assay Method for All Six Individual Vitamin B_6 Forms and Pyridoxine-β-Glucoside
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A method for determining all of the six natural vitamin B6 compounds and pyridoxine-β-glucoside in urine from humans consuming their usual diet was developed. These compounds were specifically converted with 5 enzymes into a high fluorescent 4-pyridoxolactone which was supersensitively determined by an isocratic HPLC. All of the compounds in urine from humans consuming their usual diets were for the first time determined together. The preparation procedure for urine samples was easy without HCl-hydrolysis, and the enzyme reactions took only 2 or 3 h. It required only 5 μL of the urine sample for analysis of one of the compounds. Urine samples from five young Japanese males consuming their usual diet contained pyridoxal, pyridoxamine, and pyridoxine-β-glucoside but not pyridoxine or phosphoester forms. The contents of 4-pyridoxic acid and pyridoxal correlate well with a correlation coefficient of 0.98. On the other hand, the content of pyridoxamine did not correlate with that of 4-pyridoxic acid.
- Journal of Nutritional Science and Vitaminology
Journal of Nutritional Science and Vitaminology 56(3), 157-163, 2010-06-01
Center for Academic Publications Japan