Piridoxálfoszfát

Pyridoxal phosphate, often abbreviated as PLP, is a biologically active form of vitamin B6. It acts as a cofactor for a vast array of enzymes involved in amino acid metabolism, including transamination, decarboxylation, and racemization. PLP is crucial for the synthesis and degradation of neurotransmitters, heme, and many other important biological molecules.

The synthesis of PLP begins with the absorption of vitamin B6 from the diet, which can exist as pyridoxine, pyridoxal, or pyridoxamine. These forms are then converted to pyridoxal 5'-phosphate in the liver. The hydroxyl group at the 5' position of pyridoxal is phosphorylated, forming PLP. This phosphorylation is essential for its catalytic activity.

PLP's mechanism of action typically involves forming a Schiff base intermediate with an amino group of a substrate, usually an amino acid. This interaction alters the electronic distribution within the substrate, making specific bonds more susceptible to cleavage and facilitating enzymatic reactions. Different enzymes utilize PLP in distinct ways, leading to a wide range of metabolic transformations.

A deficiency in vitamin B6, and consequently PLP, can lead to various health problems, including neurological disorders, skin lesions, and anemia. Severe deficiency is rare but can be life-threatening. PLP is involved in over 100 enzymatic reactions, highlighting its central role in fundamental metabolic pathways. Its importance extends to protein synthesis, immune function, and cognitive development.