GLS and neoplasm: Melanoma cells that were incubated with the HLA-B,C-specific mAb B1.23.2 also displayed a rapid decrease of both K-type mitochondrial glutaminase (GLS1 and GLS2), that catalyzes the hydrolysis of glutamine to glutamate and ammonia, and the alanine, serine, cysteine-preferring transporter 2 (ASCT2), which mediates the uptake of glutamine, an essential amino acid used by proliferating tumor cells (Figure 2E).