A cell-permeable, orally available thiadiazolyl-butyl-pyridazinyl compound that acts as a potent, selective, time-dependent, and slowly-reversible (t1/2 = 45 min at 25 C) inhibitor of glutaminase (IC50 = 45, 23 and 28 nM for rec hu-GAC, KGA and GAC, respectively). The inhibition appears to be...