Pyridoxal 5′-phosphate (PLP)
Overview
Pyridoxal 5′-phosphate (PLP) is the phosphorylated cofactor made from vitamin B6. The vitamers pyridoxine, pyridoxal and pyridoxamine are the dietary forms. They are converted to this phosphate; the food table reports the vitamin, not a measured amount of the cofactor [1].
PLP is the cofactor form used in amino-acid metabolism, including steps toward dopamine, serotonin and GABA. That enzyme role does not show that extra vitamin B6 raises those outputs, or that a food portion corrects a symptom [1,2].
Dietary Context
The dietary route is conversion, not a separate food constituent.
Food sources
Foods that supply vitamin B6 are listed on the vitamin B6 page. No food here is linked as containing a measured amount of pyridoxal 5′-phosphate.
Supplement versus food
A vitamin B6 supplement and a vitamin B6-containing meal both supply the vitamin precursor. Neither is a measured dose of pyridoxal 5′-phosphate [1].
Research Spotlights & Evidence Checks
Foods
Recipes
Biological Regulatory Systems
| Biological Regulatory System | Evidence-qualified relationship | Evidence |
|---|---|---|
| Neurotransmitter Regulation (BRS1) | Pyridoxal 5′-phosphate is the active cofactor formed from vitamin B6. The vitamin value does not establish a higher neurotransmitter output or a benefit from extra intake. | [1,2] |
References
[1] Spector (1978). Vitamin B6 transport in the central nervous system: in vivo studies. Non-phosphorylated vitamin B6 forms are converted to pyridoxal 5′-phosphate. A food vitamin B6 value is not a measured amount of the cofactor.
[2] Kennedy (2016). B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review. Places vitamin B6 among the cofactors used in brain metabolism. It does not show that extra intake raises neurotransmitter output.