Adenylate Kinase 3 (AK3)

The deduced 227-amino acid protein has a calculated molecular mass of 25.6 kD. AK3 shares 57.4% amino acid identity with AK4 (AK3L1). It shares 75%, 90%, and 91% amino acid identity with bovine, rat, and mouse Ak3, respectively. Northern blot analysis detected a 3.2-kb transcript in all tissues examined. Expression was highest in heart, liver, and skeletal muscle, moderate in kidney and pancreas, and weak in brain, placenta, and lung. Transcripts of 5, 1.8, and 1.35 kb were detected in heart, liver, and pancreas. Western blot analysis detected AK3 at an apparent molecular mass of 28 kD in all tissues examined. Subcellular fractionation of mouse liver and kidney detected Ak3 in the mitochondrial fraction.Human embryonic kidney cells had endogenous phosphotransferase activity, which increased following transfection of AK3 cDNA.