pyridoxal

Pyridoxal is a neuroprotectant. Pyridoxal is one of the main forms of vitamin B6. Pyridoxal is phosphorylated by pyridoxal kinase to pyridoxal phosphate (HY-B1744). Pyridoxal is oxidized by the liver to 4-pyridoxic acid (HY-113493) and excreted in the urine. Pyridoxal has shown promise in the study of carpal tunnel syndrome (CTS)[1][2][3].

ChEBI: A pyridinecarbaldehyde that is pyridine-5-carbaldehyde bearing methyl, hydroxy and hydroxymethyl substituents at positions 2, 3 and 4 respectively.

This photosensitive aldehyde form of vitamin B6 (FW = 167.16 g/mol), systematically referred to as 3-hydroxy-5-(hydroxymethyl)-2-methyl-4- pyridinecarboxaldehyde, is the immediate precursor to the coenzyme pyridoxal 5’-phosphate (PLP) and is often a weaker competitive inhibitor of PLP binding to PLP-dependent enzymes). Pyridoxal is soluble in water (1 g/2 mL) and sensitive to heat, particularly at alkaline pH. The pKa values are 4.23 (phenol OH), 8.70 (pyridinium NH+), and 13.0. Pyridoxal has a lmax value of 252 nm at pH 7.0 (e = 8200 M–1cm–1). It is typically supplied as the hydrochloride. Target(s): O-acetylhomoserine aminocarboxypropyltransferase, or O-acetylhomoserine (thiol)-lyase; alanine racemase; aldehyde dehydrogenase; arginine decarboxylase; cystathionine b-lyase, or cystine lyase; cysteine synthase; dextransucrase; b-fructofuranosidase, or invertase; glutamate dehydrogenase; hemoglobin S polymerization; hydroxyacyl-glutathione hydrolase, or glyoxalase II; kynurenine 3- monooxygenase; lactoylglutathione lyase, or glyoxalase I; NMN nucleosidase; phosphopantothenoylcysteine decarboxylase; porphobilinogen synthase, or d-aminolevulinate dehydratase; pyridoxal kinase; pyridoxal phosphatase, weakly inhibited; starch phosphorylase; thiamin phosphatase; tyrosinase; and xanthine dehydrogenase.

Human Endogenous Metabolite

[1] Vrolijk MF, et al. The vitamin B6 paradox: Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function. Toxicol In Vitro. 2017 Oct;44:206-212. DOI:10.1016/j.tiv.2017.07.009
[2] Aufiero E, et al. Pyridoxine hydrochloride treatment of carpal tunnel syndrome: a review. Nutr Rev. 2004 Mar;62(3):96-104. DOI:10.1111/j.1753-4887.2004.tb00030.x
[3] Nagata, Yoshiko, Reiko Yoda, and Yoshikazu Matsushima. "Solvolysis of pyridoxal hydrochloride in alcohols." Chemical and pharmaceutical bulletin 41.6 (1993): 1019-1022.
[4] Vrolijk, Misha F., et al. "The vitamin B6 paradox: Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function." Toxicology In Vitro 44 (2017): 206-212. DOI:10.1016/j.tiv.2017.07.009