| 词条 | 4-Hydroxyphenylglycine |
| 释义 |
| Name = 4-Hydroxyphenylglycine | ImageFile = HPG figure.png | ImageCaption = 4-Hydroxyphenylglycine (HPG). (R)-L-HPG shown on left; (S)-D-HPG shown on right. | OtherNames = 3-Amino-2,3,6-trideoxy-3-methyl-L-lyxo-hexopyranose | IUPACName = Nortyrosine | SystematicName = 2-Amino-2-(4-hydroxyphenyl)acetic acid | Section1 = {{Chembox Identifiers | ChemSpiderID = 83189 | InChIKey = LJCWONGJFPCTTL-UHFFFAOYSA-N | CASNo = 37784-25-1 | PubChem = 92143 | EC_number = 213-353-2 | ChEMBL = 130865 | ChEBI = 50418 | ChEBI1 = 15695 | ChEBI1_Comment = D | Beilstein = 513130 | UNII = 7UYG7X0F53 | KEGG1 = C03493 | KEGG1_Comment = D | SMILES = C1=CC(=CC=C1C(C(=O)O)N)O }} | Section2 = {{Chembox Properties | C=8 | H=9 | N=1 | O=3 }} | Section3 = | Section4 = | Section5 = | Section6 = }} 4-Hydroxyphenylglycine (HPG) is a non-proteogenic amino acid found in vancomycin and related glycopeptides. HPG is synthesized from the shikimic acid pathway and requires four enzymes to synthesize:[1] Both L- and D-HPG are used in the vancomycin class of antibiotics. Tyrosine, a similar amino acid, differs by a methylene group (CH2) between the aromatic ring and the alpha carbon. BiosynthesisHPG is synthesized from prephenate, an intermediate in the shikimic acid pathway and also a precursor to tyrosine. Prephenate is aromatized by prephenate dehydrogenase (Pdh) using NAD+ as a cofactor to produce 4-hydroxyphenylpyruvate. 4-Hydroxyphenylpyruvate is then oxidized by 4-hydroxymandelate synthase (4HmaS) using oxygen to form 4-hydroxymandelate and hydrogen peroxide. 4HmaS is a non-heme iron-dependent dioxygenase. The reaction mechanism of this unique oxidation was proposed by Choroba et al in 2000[2] 4-Hydroxymandelate is subsequently oxidized by hydroxymandelate oxidase (Hmo) to 4-hydroxylbenzoylformate, using FMN as a cofactor.[3] Finally, 4-hydroxyphenylglycine transaminase (HpgT) transfers an ammonia moiety from a donor to 4-hydroxylbenzoylformate to form HPG. Several different molecules can serve as the nitrogen donor for the transamination, however, Hubbard et al suspect L-tyrosine to serve as the most efficient donor.[4] By doing so, the following cycle is constructed: HPG is also synthesized in Herpetosiphon aurantiacus using enzymes Haur_(1871,1887,1888).[5] See also
References1. ^Yim, G., Thaker, M. N., Koteva, K., Wright, G. "Glycopeptide antibiotic biosynthesis." The Journal of Antibiotics, 2017, 67, 31-41. {{Non-proteinogenic amino acids}}{{DEFAULTSORT:Hydroxyphenylglycine, 4-}}2. ^Choroba, O. W., Williams, D. H., Spencer, J. B. "Biosynthesis of the Vancomycin Group of Antibiotics: Involvement of an Unusual Dioxygenase in the Pathway to (S)-4-Hydroxyphenylglycine." J. Am. Chem. Soc. 2000, 122, 5389-5390. 3. ^Li, T.-L., Choroba, O. W., Charles, E. H., Sandercock, A. M., Williams, D. H., Spencer, J. B. "Characterisation of a hydroxymandelate oxidase involved in the biosynthesis of two unusual amino acids occurring in the vancomycin group of antibiotics." Chem. Commun., 2001, 1752-1753. 4. ^Hubbard, B. K., Thomas, M. G., Walsh, C. T. "Biosynthesis of L-p-hydroxyphenylglycine, a non-proteogenic amino acid constituent of peptide antibiotics." Chemistry & Biology, 2000, 7 (12), 931-942. 5. ^Kastner, S., Müller, S., Natesan, L., König, G. M., Guthke, R., Nett, M. "4-Hydroxyphenylglycine biosynthesis in Herpetosiphon aurantiacus: a case of gene duplication and catalytic divergence." Arch. Microbiol. 2012, 194, 557-566. 1 : Non-proteinogenic amino acids |
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