PKR activator 1 is a potent activator of pyruvate kinase-R (PKR).

Four isoforms of Pyruvate kinase (PK) are found in mammals: L and R isoforms, produced by the PKLR gene, are expressed in the liver and red blood cells, respectively. The PKM gene is responsible for two splice variants: M1, prevalent in most adult tissues, and M2, found during embryonic development and in specific adult tissues, such as the kidney and hematopoietic stem cells. Additionally, many tumor cells express PKM2. This tetrameric isoform, which is allosterically regulated, is naturally predisposed to suppress its activity through several mechanisms: post-translational modifications, allosteric alterations by small molecules including certain amino acids, and conversion into a dimeric form. These processes lead to a partial blockade of glycolysis at its final stage[1].