Abstract
Tetrahydrobiopterin (BH4) is an essential cofactor for biosynthesis of dopamine, noradrenaline, adrenaline, serotonin, melatonin, and nitric oxide. These molecules are physiologically important neurotransmitters and hormones, and thus the BH4 level in the cells is critical for their function. BH4 is synthesized from GTP through three enzymatic reactions. Because BH4 is easily oxidized to dihydrobiopterin (BH2), the ratio of BH4 to BH2 could be an index of the oxidative stress in the cell. Here, we introduce the post-column oxidation method developed by Tani and Ohno for discriminative quantitation of the reduced forms of pteridines, including BH4, BH2, and biopterin, in biological samples.
