| Pyroglutamic acid | |
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Pidolic acid |
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5-Oxopyrrolidine-2-carboxylic acid |
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Other names
5-Oxoproline |
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| Identifiers | |
| Abbreviations | Glp |
| CAS number | 98-79-3 (2S) , 4042-36-8 (2R), 149-87-1 |
| PubChem | 7405 (2S), 439685 (2R), 499, 10534703 (2S)(3,4-3H2) |
| ChemSpider | 7127 (2S) , 388752 (2R) , 485 , 8710094 (2S)(3,4-3H2) |
| UNII | SZB83O1W42 |
| EC number | 205-748-3 |
| DrugBank | DB03088 |
| KEGG | C02237 |
| MeSH | Pyrrolidonecarboxylic+acid |
| ChEBI | CHEBI:16010 |
| ChEMBL | CHEMBL284718 |
| RTECS number | TW3710000 |
| Beilstein Reference | 82134 |
| Gmelin Reference | 1473408 |
| 3DMet | B01549 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C5H7NO3 |
| Molar mass | 129.11 g mol−1 |
| Exact mass | 129.042593095 g mol-1 |
| Melting point |
184 °C, 457 K, 363 °F |
| log P | -0.89 |
| Acidity (pKa) | -1.76, 3.48, 12.76 |
| Basicity (pKb) | 15.76, 10.52, 1.24 |
| Isoelectric point | 0.94 |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Pyroglutamic acid (also known as 5-oxoproline, pidolic acid, or pyroglutamate for its basic form) is an uncommon amino acid derivative in which the free amino group of glutamic acid cyclizes to form a lactam. It is found in many proteins including bacteriorhodopsin. N-terminal glutamine residues can spontaneously cyclize to become pyroglutamate. This is one of several forms of blocked N-terminals which present a problem for N-terminal sequencing using Edman chemistry, which requires a free primary amino group not present in pyroglutamic acid. The enzyme pyroglutamate aminopeptidase can restore a free N-terminus by cleaving off the pyroglutamate residue.[1]
Pyroglutamic acid is also known as pidolic acid, exists as two distinct isomers:
The sodium salt of pyroglutamic acid – known either as sodium pyroglutamate or sodium pidolate – is used on the skin to retain moisture.
Pyroglutamic acid is sold as a dietary supplement in the United States.
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