Pyridoxyl phosphate targets multiple enzymes. It is a coenzyme for a wide range of PLP-dependent enzymes involved in amino acid metabolism. It also acts as an inhibitor of reverse transcriptases and as a purinergic P2 receptor antagonist.

Pyridoxal phosphate produces an instantaneous drop in the rate of DNA synthesis and strongly inhibits RNase H and DNA polymerase [1]. Pyridoxal phosphate binding totally inhibits NEIL2. Pyridoxal phosphate-polymerized NEIL2 displayed fold reduced activity than the intact enzyme over a wide variety of enzyme/substrate interactions. Following conjugation with pyridoxal phosphate, NEIL2 loses its capacity to bind THF ligand [2].
In vitro, Pyridoxyl phosphate acts as a coenzyme for PLP-dependent enzymes and as an inhibitor of reverse transcriptases. Its activity is characterized by its ability to participate in enzymatic reactions as a cofactor and to inhibit specific enzymes.

In vivo, Pyridoxyl phosphate is the active form of vitamin B6 and is essential for various metabolic processes. It is used for the treatment of tardive dyskinesia.

The in vitro activity of Pyridoxyl phosphate as a coenzyme is assessed using enzyme activity assays. PLP-dependent enzymes are incubated with their substrates and PLP, and the enzymatic activity is measured. The inhibition of reverse transcriptase is assessed using cell-free enzyme assays.

For cellular assays, Pyridoxyl phosphate is used as a supplement in cell culture media to support cellular metabolism. Its effects on cellular functions can be studied in various cell types.

In vivo, Pyridoxyl phosphate is administered as a vitamin B6 supplement or as a therapeutic agent for tardive dyskinesia. It is typically administered orally or by injection.

Pyridoxyl phosphate has a molecular weight of 247.14 g/mol and a molecular formula of C8H10NO6P. It is a white to off-white crystalline powder that is soluble in water. It should be stored at -20°C.

Pyridoxyl phosphate is generally well-tolerated as a vitamin B6 supplement. High doses may cause neuropathy. It is contraindicated in patients with hypersensitivity to vitamin B6.

[1]. Modak MJ. Pyridoxal 5' phosphate: a selective inhibitor of oncornaviral DNA polymerases. Biochem Biophys Res Commun. 1976 Jul 12;71(1):180-7.

[2]. Inactivation of NEIL2 DNA glycosylase by pyridoxal phosphate reveals a loop important for substrate binding. Biochem Biophys Res Commun. 2010 Mar 26;394(1):100-5.

Pyridoxal phosphate is a monophosphate ester obtained by the condensation of phosphate and the primary hydroxyl group of pyridoxal. It is a coenzyme and a metabolite in humans, E. coli, Saccharomyces cerevisiae, and mice. It is also an inhibitor and cofactor of EC 2.7.7.7 (DNA-directed DNA polymerase). It is a vitamin B6 phosphate ester, belonging to the methylpyridine, monohydroxypyridine, and pyridinecarboxaldehyde classes. Functionally, it is related to pyridoxal. It is the conjugate acid of pyridoxal phosphate (2-). It is the active form of vitamin B6 and participates as a coenzyme in the synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, and aminolevulinic acid. During amino acid transamination, pyridoxal phosphate is transiently converted to pyridoxamine phosphate (pyridoxamine). Medicare's MC-1 drug is a cardioprotective agent designed to reduce damage to the heart during arterial blockage and arterial reopening after bypass surgery. Pyridoxal phosphate is present in or produced by E. coli (K12 strain, MG1655 strain).
Pyridoxal phosphate has been reported to exist in Arabidopsis thaliana, humans, and other organisms with relevant data.
Pyridoxal phosphate is the active form of vitamin B6 and a coenzyme for many pyridoxal phosphate (PLP)-dependent enzymes. PLP participates in various enzymatic transamination, decarboxylation, and deamination reactions; pyridoxal-5'-phosphate is essential for the synthesis of amino acids and their metabolites, and also participates in the synthesis and/or catabolism of certain neurotransmitters, including the conversion of glutamate to γ-aminobutyric acid (GABA) and the conversion of levodopa to dopamine. In vitamin B6 deficiency, pyridoxal-5'-phosphate can be used as a dietary supplement. Decreased levels of pyridoxal-5'-phosphate in the brain can lead to neurological dysfunction.
Pyridoxal-5'-phosphate is a metabolite found or produced in Saccharomyces cerevisiae.
It is the active form of vitamin B6 and acts as a coenzyme in the synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, and aminolevulinic acid. During amino acid transamination, pyridoxal phosphate is temporarily converted to pyridoxamine phosphate (pyridoxamine).
See also: Pyridoxal (note moved to).
Pharmaceutical Indications
For nutritional supplementation and treatment of dietary deficiencies or imbalances.
Investigated for the treatment of coronary artery disease.
Mechanism of Action
Pyridoxal phosphate is a coenzyme in many enzymatic reactions. It is the active form of vitamin B6 and consists of three natural organic compounds: pyridoxal, pyridoxamine, and pyridoxine. Pyridoxal phosphate acts as a coenzyme in all transamination reactions as well as in the oxidation and deamination of certain amino acids. The aldehyde group of pyridoxal phosphate forms a Schiff base bond with the ε-amino group of a specific lysine residue of an aminotransferase. The α-amino group of the amino acid substrate replaces the ε-amino group of the lysine residue at the active site. The resulting imine is deprotonated to form a quinone intermediate, which subsequently accepts a proton at another position to form a ketoimine. After hydrolysis of the ketoimine, the amino group remains on the protein complex. MC-1 is a biologically active natural product that can be considered a chemical entity that has been evolutionarily selected and validated to bind to specific protein domains. Therefore, its potential structural framework (or backbone) has been biologically proven to be safe and effective, providing strong guiding principles for the development of new drugs and compound libraries.
Pyridoxyl phosphate is the active form of vitamin B6 and is essential for human health. It is used as a dietary supplement and as a therapeutic agent for certain conditions, including tardive dyskinesia. It is also used as a research tool to study PLP-dependent enzymes.

C8H10NO6P

247.14

247.024

54-47-7

Pyridoxal phosphate-d5;1246818-16-5

1051

Off-white to yellow solid powder

1.6±0.1 g/cm3

565.7±60.0 °C at 760 mmHg

255 °C

296.0±32.9 °C

0.0±1.6 mmHg at 25°C

1.641

-0.52

3

7

4

16

292

0

CC1=NC=C(C(=C1O)C=O)COP(=O)(O)O

NGVDGCNFYWLIFO-UHFFFAOYSA-N

InChI=1S/C8H10NO6P/c1-5-8(11)7(3-10)6(2-9-5)4-15-16(12,13)14/h2-3,11H,4H2,1H3,(H2,12,13,14)

(4-formyl-5-hydroxy-6-methylpyridin-3-yl)methyl dihydrogen phosphate

MC 1; MC1; MC-1

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~62.5 mg/mL (~252.89 mM)
H2O : ~5 mg/mL (~20.23 mM)

Solubility in Formulation 1: 2 mg/mL (8.09 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication (<60°C).

---

 (Please use freshly prepared in vivo formulations for optimal results.)