one of three rate-limiting enzymes in glycolysis. It catalyzes the transfer of a phosphate group from phosphoenolpyruvate (PEP) to ADP, yielding one molecule ATP and a pyruvate molecule, which is a central metabolic intermediate that can be used as a building block or oxidized further. Overexpressed in a variety of cancers. Interacts with thyroid hormone, and thus may mediate cellular metabolic effects induced by thyroid hormones. Binds Opa protein, a bacterial outer membrane protein involved in gonococcal adherence to and invasion of human cells, suggesting a role of this protein in bacterial pathogens is. There are several mammalian isozymes of pyruvate kinase encoded by different genes. The L type predominates in liver, and the M type in muscle and brain. Two alternatively spliced human isoforms of PKM2 have been reported. Note: This description may include information from UniProtKB.