Abstract: Glutamine antagonists and their use for treating oncological, immunological, and neurological diseases are disclosed. Also disclosed are methods for treating an oncological, immunological, infectious or neurological disease or disorder, the method comprising administering to a subject in need of treatment thereof a therapeutically effective amount of a glutamine antagonist of the disclosure or the pharmaceutical composition thereof. Also disclosed are methods of enhancing the effects of an immune checkpoint inhibitor, enabling a subject to respond to an immune checkpoint inhibitor, or enabling the toxicity or the dose or number of treatments with an immune checkpoint inhibitor to be reduced, comprising administering to a subject in need of treatment thereof a therapeutically effective amount of a glutamine antagonist of the disclosure or the pharmaceutical composition thereof, and an immune checkpoint inhibitor.

Abstract: The presently disclosed subject matter provides methods for quantifying levels of glutamine antagonists, such as 6-diazo-5-oxo-L-norleucine (DON), including such glutamine antagonists resulting from in vivo conversion of ester prodrugs of such glutamine antagonists, in a biological sample.

Abstract: Described herein are high-throughput methods of monitoring D-serine levels in plasma. The assay involves the use of strong cation solid phase extraction (SPE) to isolate D-serine from plasma, followed by quantitation of D-serine using the D-amino acid oxidase- (DAAO-) catalyzed reaction. Also described are methods of screening for compounds that act as DAAO inhibitors.