Biopterin 6 Neopterin 6 article 4 biopterin 4 chemistry 4 metabolism 4 neopterin 4 7,8 dihydroneopterin 2 7,8-dihydrobiopterin 2 7,8-dihydroneopterin 2 Anaerobic conditions 2 Aqueous solutions 2 Biological functions 2 Chromatography, High Pressure Liquid 2 Cytochromes c 2 Dimerization 2 Heterocyclic compound 2 Humans 2 Isomerism 2 Living systems 2 Macrophages 2 Magnetic Resonance Spectroscopy 2 Molecular Structure 2 NMR analysis 2 Nuclear magnetic resonance 2 Oxygen 2 Photochemistry 2 Photolysis 2 Solutions 2 Spectrometry, Mass, Electrospray Ionization 2