Pyruvate Kinase M (PKM) is a crucial enzyme in glycolysis, catalyzing the final step of this metabolic pathway. It exists in two isoforms, PKM1 and PKM2, which are generated through alternative splicing of the PKM gene. PKM1 is predominantly found in differentiated tissues with high metabolic demands, while PKM2 is expressed in embryonic tissues, adult stem cells, and notably, in many cancer cells. PKM2's unique allosteric regulation allows it to switch between highly active tetrameric and less active dimeric forms, thereby controlling glucose flux to support either ATP production or anabolic processes essential for cell proliferation.