pyridoxal

{{Hatnote|Not to be confused with pyridoxol, which is pyridoxine.}}

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 464377081

| Name = Pyridoxal

| ImageFile_Ref = {{chemboximage|correct|??}}

| ImageFile = Pyridoxal.png

| ImageClass = skin-invert-image

| ImageSize = 185px

| ImageName = Skeletal formula of pyridoxal

| ImageCaption = Idealised skeletal formula

| ImageFile1 = Pyridoxal-from-xtal-3D-bs-17.png

| ImageClass1 = bg-transparent

| ImageName1 = Ball-and-stick model of pyridoxal

| ImageCaption1 = Ball-and-stick model based on the crystal structure.{{cite journal | url = https://www.ccdc.cam.ac.uk/structures/Search?Ccdcid=1110663&DatabaseToSearch=Published | title = CSD Entry: BIHKEI01 | website = Cambridge Structural Database: Access Structures | year = 1985 | publisher = Cambridge Crystallographic Data Centre | access-date = 2023-11-04 | archive-date = 2023-11-04 | archive-url = https://web.archive.org/web/20231104214416/https://www.ccdc.cam.ac.uk/structures/Search?Ccdcid=1110663&DatabaseToSearch=Published | url-status = live }}{{ cite journal | first1 = C. L. | last1 = MacLaurin | first2 = M. F. | last2 = Richardson | title = Pyridoxal, C₈H₉NO₃, and pyridoxamine dihydrate, C₈H₁₂N₂O₂.2H₂O | journal = Acta Crystallogr. C | year = 1985 | volume = 41 | issue = 2 | pages = 261–263 | doi = 10.1107/S0108270185003547 | bibcode = 1985AcCrC..41..261M }} Note that the acidic phenol group has donated a proton to the basic pyridine group to form a zwitterion, and the hydroxymethyl group has reacted with the aldehyde group to form a hemiacetal.

| PIN =3-Hydroxy-5-(hydroxymethyl)-2-methylpyridine-4-carbaldehyde

|Section1={{Chembox Identifiers

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 3THM379K8A

| UNII1_Ref = {{fdacite|correct|FDA}}

| UNII1 = 1416KF0QBC

| UNII1_Comment = (hydrochloride)

| ChEMBL_Ref = {{ebicite|correct|EBI}}

| ChEMBL = 102970

| KEGG_Ref = {{keggcite|correct|kegg}}

| KEGG = C00250

| InChI = 1/C8H9NO3/c1-5-8(12)7(4-11)6(3-10)2-9-5/h2,4,10,12H,3H2,1H3

| InChIKey = RADKZDMFGJYCBB-UHFFFAOYAP

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C8H9NO3/c1-5-8(12)7(4-11)6(3-10)2-9-5/h2,4,10,12H,3H2,1H3

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = RADKZDMFGJYCBB-UHFFFAOYSA-N

| CASNo = 66-72-8

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo2_Ref = {{cascite|correct|CAS}}

| CASNo2 = 65-22-5

| CASNo2_Comment = (hydrochloride)

| PubChem = 1050

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 1021

| DrugBank_Ref = {{drugbankcite|correct|drugbank}}

| DrugBank = DB00147

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 17310

| SMILES = O=Cc1c(O)c(C)ncc1CO

}}

|Section2={{Chembox Properties

| Formula = C₈H₉NO₃

| MolarMass = 167.16 g/mol

| MeltingPtC = 165

| MeltingPt_notes = (decomposes)

}}

|Section3={{Chembox Related

| OtherFunction_label = arylformaldehydes

| OtherFunction = Damnacanthal

Gossypol

}}

}}

Pyridoxal (PL){{Cite web |title=Vitamin B-6 |url=https://iupac.qmul.ac.uk/misc/B6.html |access-date=2024-09-26 |website=iupac.qmul.ac.uk}} is one form of vitamin B₆.

Some medically relevant bacteria, such as those in the genera Granulicatella and Abiotrophia, require pyridoxal for growth. This nutritional requirement can lead to the culture phenomenon of satellite growth. In in vitro culture, these pyridoxal-dependent bacteria may only grow in areas surrounding colonies of bacteria from other genera ("satellitism") that are capable of producing pyridoxal.

Pyridoxal is involved in what is believed to be the most ancient reaction of aerobic metabolism on Earth, about 2.9 billion years ago, a forerunner of the Great Oxidation Event."Protein Domain Structure Uncovers the Origin of Aerobic Metabolism and the Rise of Planetary Oxygen", Gustavo Caetano-Anolles et al., published in Structure; paper available from University of Illinois News Bureau, 2012.