1.0 2011-09-21 01:50:29 UTC 2015-07-21 06:59:38 UTC FDB029125 13'-Hydroxy-alpha-tocopherol 13'-hydroxy-alpha-tocopherol is the precursor in dehydrogenation to 13'-carboxy-alpha-tocopherol by an unidentified microsomal enzyme(s) probably via an aldehyde intermediate The tocopherols ( a-tocopherol , b-tocopherol ,r-tocopherol and d-tocopherol ) and their corresponding tocotrienols are synthesized by plants and have vitamin E antixoidant activity (see pathway vitamin E biosynthesis ). They differ in the number and location of methyl groups on the chromanol ring. The naturally occurring form of a-tocopherol is (2R,4'R,8'R)-a-tocopherol (synonym (R,R,R)-a-tocopherol). Synthetic a-tocopherols are a racemic mixture of eight different R and S stereoisomers. Only the 2R forms are recognized as meeting human requirements. The in vivo function of vitamin E is to scavenge peroxyl radicals via its phenolic (chromanol) hydroxyl group, thus protecting lipids against free radical-catalyzed peroxidation. The tocopheryl radical formed can then be reduced by reductants such as L-ascorbate. Other major products of a-tocopherol oxidation include α-tocopherylquinone and epoxy-a-tocopherols. The metabolites a-tocopheronic acid and its lactone, known as the Simon metabolites, are generally believed to be artefacts. In addition to these oxidation products, the other major class of tocopherol metabolites is the carboxyethyl-hydroxychromans.These metabolites are produced in significant amounts in response to excess vitamin E ingestion. Vitamin E is fat-soluble and its utilization requires intestinal fat absorption mechanisms. It is secreted from the intestine into the lymphatic system in chylomicrons which subsequently enter the plasma. Lipolysis of these chylomicrons can result in delivery of vitamin E to tissues, transfer to high-density lipoproteins (and subsequently to other lipoproteins via the phospholipid exchange protein), or retention in chylomicron remnants. These remnants are taken up by the liver. Natural (R,R,R)-α-tocopherol and synthetic 2R-α-tocopherols are then preferentially secreted from the liver into plasma as a result of the specificity of the α-tocopherol transfer protein. This protein, along with the metabolism of excess vitamin E in the liver and excretion into urine and bile, mediate the supply of a-tocopherol in plasma and tissues [HMDB] 2-(13-Hydroxy-4,8,12-trimethyltridecyl)-6-hydroxy-2,5,7,8-tetramethylchroman C29H50O3 446.7055 446.375995466 (2R)-2-[(4R,8S)-13-hydroxy-4,8,12-trimethyltridecyl]-2,5,7,8-tetramethyl-3,4-dihydro-2H-1-benzopyran-6-ol (2R)-2-[(4R,8S)-13-hydroxy-4,8,12-trimethyltridecyl]-2,5,7,8-tetramethyl-3,4-dihydro-1-benzopyran-6-ol CC(CO)CCC[C@@H](C)CCC[C@@H](C)CCC[C@]1(C)CCC2=C(O1)C(C)=C(C)C(O)=C2C InChI=1S/C29H50O3/c1-20(13-9-14-22(3)19-30)11-8-12-21(2)15-10-17-29(7)18-16-26-25(6)27(31)23(4)24(5)28(26)32-29/h20-22,30-31H,8-19H2,1-7H3/t20-,21+,22?,29+/m0/s1 URYLCCKXLNXSRS-XIRVVSDESA-N belongs to the class of organic compounds known as tocopherols. These are vitamin E derivatives containing a saturated trimethyltridecyl chain attached to the carbon C6 atom of a benzopyran ring system. The differ from tocotrienols that contain an unsaturated trimethyltrideca-3,7,11-trien-1-yl chain. Tocopherols Organic compounds Lipids and lipid-like molecules Prenol lipids Quinone and hydroquinone lipids Aromatic heteropolycyclic compounds 1-benzopyrans Alkyl aryl ethers Benzenoids Diterpenoids Hydrocarbon derivatives Long-chain fatty alcohols Oxacyclic compounds Primary alcohols 1-benzopyran Alcohol Alkyl aryl ether Aromatic heteropolycyclic compound Benzenoid Benzopyran Chromane Diterpenoid Ether Fatty acyl Fatty alcohol Hydrocarbon derivative Long chain fatty alcohol Organic oxygen compound Organoheterocyclic compound Organooxygen compound Oxacycle Primary alcohol Tocopherol chromanol phenols primary alcohol Solid logp 8.07 ALOGPS logs -7.08 ALOGPS solubility 3.70e-05 g/l ALOGPS logp 9.15 ChemAxon pka_strongest_acidic 10.8 ChemAxon pka_strongest_basic -1.7 ChemAxon iupac (2R)-2-[(4R,8S)-13-hydroxy-4,8,12-trimethyltridecyl]-2,5,7,8-tetramethyl-3,4-dihydro-2H-1-benzopyran-6-ol ChemAxon average_mass 446.7055 ChemAxon mono_mass 446.375995466 ChemAxon smiles CC(CO)CCC[C@@H](C)CCC[C@@H](C)CCC[C@]1(C)CCC2=C(O1)C(C)=C(C)C(O)=C2C ChemAxon formula C29H50O3 ChemAxon inchi InChI=1S/C29H50O3/c1-20(13-9-14-22(3)19-30)11-8-12-21(2)15-10-17-29(7)18-16-26-25(6)27(31)23(4)24(5)28(26)32-29/h20-22,30-31H,8-19H2,1-7H3/t20-,21+,22?,29+/m0/s1 ChemAxon inchikey URYLCCKXLNXSRS-XIRVVSDESA-N ChemAxon polar_surface_area 49.69 ChemAxon refractivity 137.23 ChemAxon polarizability 57.32 ChemAxon rotatable_bond_count 13 ChemAxon acceptor_count 3 ChemAxon donor_count 2 ChemAxon physiological_charge 0 ChemAxon formal_charge 0 ChemAxon Specdb::CMs 9723 Specdb::CMs 39958 Specdb::CMs 135983 Specdb::CMs 143717 Specdb::MsMs 287455 Specdb::MsMs 287456 Specdb::MsMs 287457 Specdb::MsMs 326320 Specdb::MsMs 326321 Specdb::MsMs 326322 Specdb::MsMs 2309688 Specdb::MsMs 2309689 Specdb::MsMs 2309690 Specdb::MsMs 2656798 Specdb::MsMs 2656799 Specdb::MsMs 2656800 HMDB12559