BPTES is an allosteric inhibitor of kidney-type glutaminase 1 (GLS1; IC50 = 3.3 μM) that drives the formation of inactive GLS1 tetramers. It is selective for GLS1 over GLS2, glutamate dehydrogenase, and γ-glutamyl transpeptidase. BPTES decreases glutaminase activity and reduces proliferation of aerobic P493 cells as well as induces cell death, increases the production of reactive oxygen species (ROS), and reduces ATP levels in hypoxic P493 cells. It also decreases ATP-linked and uncoupled oxygen consumption in C2C12 myotubes when used in combination with UK 5099 and/or etomoxir. In vivo, BPTES (12.5 mg/kg) reduces tumor volume in a P493 lymphoma mouse xenograft model.