Vitamin B6 (Pyridoxine)
Vitamin B6 (Pyridoxine) refers to a group of water-soluble vitamins important in metabolic reactions via its active form, PLP (pyridoxal 5′-phosphate).
PLP is involved in a number of enzymatic reactions: transamination reactions (e.g. ALT in Pyruvate Metabolism), decarboxylation reactions (e.g. DOPA decarboxylase in Catecholamine Synthesis), and that of glycogen phosphorylase (supplemental treatment for McArdle Disease). PLP is also involved in neurotransmitter synthesis, cystathionine synthesis (see Homocysteine Metabolism), histamine synthesis, Heme Synthesis, and gene expression.
Given its important physiologic roles, Vitamin B6 Deficiency can present with many signs and symptoms. Examples include neuropathy (paresthesias), convulsions and a sideroblastic anemia secondary to ALA synthase dysfunction (see Heme Synthesis). Vitamin B6 can be caused by a variety of reasons, but classically is seen in the setting of oral contraceptive or isoniazid use.
Find Vitamin B6 and other Vitamins among Pixorize's visual mnemonics for the USMLE Step 1 and NBME shelf exams.