TOPICS: Required for transaminases, alanine aminotransferase (ALT), aspartate aminotransferase (AST), required for decarboxylation reactions, dopa decarboxylase, dopamine, norepinephrine, epinephrine, production of neurotransmitters, serotonin, GABA, glycogen phosphorylase, heme synthesis, niacin (B3), histamine, cystathionine, convulsions, cystathionine synthase, homocysteine, cysteine, pyridoxine deficiency, isoniazid, hyperirritability, peripheral neuropathy, oral contraceptives, sideroblastic anemia