Pyridoxal 5'-phosphate monohydrate, which is also called P5P, PLP; the molecular formula is C8H10NO6P.H2O, the molecular weight is 265.1571, the CAS number is: 41468-25-1.

Pyridoxal phosphate (PLP, the main metabolically active form of vitamin B6) is a multifunctional coenzyme involved in the metabolism of amino compounds, and enzymes that use it as a coenzyme factor are called PLP-dependent enzymes (PLP-dependent enzymes, PLP- DEs), which play an important role in the metabolism of sugars, lipids and amino acids. Mainly the biosynthesis of amino acids and biomolecules such as the neurotransmitters serotonin, dopamine, epinephrine, norepinephrine, gamma-aminobutyric acid (GABA), and histamine.