. . "L-Proline, 5-oxo-"@en . . "5-Ketoproline"@en . "C0034330" . "Pyroglutamic Acid"@en . . "Pyrrolidonecarboxylic Acid"@en . "Pidolic Acid"@en . . "5-Oxoproline"@en . "D011761" . . "5-Oxopyrrolidine-2-Carboxylic Acid"@en . . . "Pyrrolidonecarboxylic Acid"@en . .