Vitamin B6 (Pyridoxine) is a water-soluble vitamin that serves as a coenzyme in over 100 enzymatic reactions, primarily in protein metabolism. It is essential for the synthesis of neurotransmitters such as serotonin, dopamine, and gamma-aminobutyric acid (GABA). Vitamin B6 plays a crucial role in immune function, hemoglobin synthesis, and the metabolism of amino acids.