AK9 (Adenylate Kinase 9): Adenylate kinase 9 is a gene that encodes an enzyme from the adenylate kinase family, which catalyses the reversible transfer of phosphate groups between adenine nucleotides, primarily ATP and AMP. AK9 is localised to the mitochondria, where it supports energy metabolism and nucleotide balance. By facilitating ATP-AMP interconversion, it helps regulate cellular energy levels and contributes to processes such as mitochondrial function, apoptosis, and stress responses. Dysregulation of AK9 may affect metabolic and cellular homeostasis.