Iduronic acid

{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 461775688 | ImageFile = Haworth L-iduronic acid.svg | ImageSize = 100px | IUPACName = {{sm|l}}-idopyranuronic acid | OtherNames = {{sm|l}}-Iduronic acid, {{sm|d}}-ido-Hexuronic acid, IdoA |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 10051462 | InChI = 1/C6H10O7/c7-1-2(8)4(5(10)11)13-6(12)3(1)9/h1-4,6-9,12H,(H,10,11)/p-1/t1-,2-,3+,4+,6+/m0/s1 | InChIKey = AEMOLEFTQBMNLQ-QQSWGHAIBB | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C6H10O7/c7-1-2(8)4(5(10)11)13-6(12)3(1)9/h1-4,6-9,12H,(H,10,11)/p-1/t1-,2-,3+,4+,6+/m0/s1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = AEMOLEFTQBMNLQ-VCSGLWQLSA-M | CASNo_Ref = {{cascite|correct|CAS}} | CASNo1 = 3402-98-0 | CASNo1_Comment = racemate | CASNo = 2073-35-0 | CASNo_Comment = L-enantiomer | CASNo2 = | CASNo2_Comment =

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

| UNII = F5HD8XQ3DP | PubChem = 11877134 | SMILES = [O-]C(=O)[C@@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O | MeSHName = Iduronic+acid | ChEBI_Ref = {{ebicite|changed|EBI}} | ChEBI = 28481 | KEGG_Ref = {{keggcite|changed|kegg}} | KEGG = C06472 }} |Section2={{Chembox Properties | C=6 | H=10 | O=7 | MolarMass = 194.139 g/mol | Appearance = white solid | Density = | MeltingPtC = 131-132 | BoilingPt = | Solubility = }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }} {{sm|l}}-'''Iduronic acid''' (IUPAC abbr.: '''IdoA''') is the major uronic acid component of the glycosaminoglycans (GAGs) dermatan sulfate, and heparin. It is also present in heparan sulfate, although here in a minor amount relative to its carbon-5 epimer glucuronic acid. IdoA is a pyranose sugar. Most pyranoses are stable in one of two chair conformations ¹C₄ or ⁴C₁. {{sm|l}}-iduronate is different and adopts more than one solution conformation, with an equilibrium existing between three low-energy conformers. These are the ¹C₄ and ⁴C₁ chair forms and an additional ²S₀ skew-boat conformation.{{citation needed|date=April 2024}}

thumb|left|α-{{sm|l}}-idopyranuronic acid|120px

IdoA may be modified by the addition of an ''O''-sulfate group at carbon position 2 to form 2-''O''-sulfo-{{sm|l}}-iduronic acid (IdoA2S).

In 2000, LK Hallak described the importance of this sugar in respiratory syncytial virus (RSV) infection. Dermatan sulfate and heparan sulfate were the only GAGs containing IdoA, and they were the only ones that inhibited RSV infection in cell culture.<ref>{{cite journal |journal=Virology |year=2000 |volume=271 |pages=264–75 |title=Iduronic acid-containing glycosaminoglycans on target cells are required for efficient respiratory syncytial virus infection |vauthors=Hallak LK, Collins PL, Knudson W, Peeples ME |doi=10.1006/viro.2000.0293 |pmid=10860881 |issue=2|doi-access=free }}</ref>

When internally positioned within an oligosaccharide, the ¹C₄ and ²S₀ conformations (shown below for IdoA2S) predominate.

Proton NMR spectroscopy can be used to track changes in the balance of this equilibrium.<ref>{{cite journal |vauthors=Ferro DR, Provasoli A, Ragazzi M, Casu B, Torri G, Bossennec V, Perly B, Sinaÿ P, Petitou M, Choay J| title=Conformer populations of L-iduronic acid residues in glycosaminoglycan sequences | journal=Carbohydrate Research| year=1990 | volume=195 | pages=157–167 | pmid=2331699 | doi=10.1016/0008-6215(90)84164-P | issue=2}}</ref>

<gallery class="center"> File:IDU_1C4.jpeg|'''IdoA(2S)¹C₄ conformation''' File:IDU_2S0.jpeg|'''IdoA(2S)²S₀ conformation''' </gallery>

Iduronic acid can be detected colorimetrically.<ref>{{cite journal |doi=10.1021/ac50043a036 |title=Colorimetric determination of hexuronic acids in plant materials |date=1979 |last1=Scott |first1=Ralph W. |journal=Analytical Chemistry |volume=51 |issue=7 |pages=936–941 }}</ref>

== See also ==

* Idose

==References== <references/>

Category:Uronic acids Category:Pyranoses Category:Hexoses