... 1, Pyridoxal phosphate, the metabolically active form of vitamin B6, is involved in many aspects of macronutrient metabolism, ... and then from selenohomocysteine to hydrogen selenide. Vitamin B6 is also required for the conversion of tryptophan to ... (GABA), and dihydroxyphenylalanine to dopamine. 3,Gluconeogenesis Vitamin B6 also plays a role in gluconeogenesis. Pyridoxal phosphate can ...