ACE2, also known as angiotensin-converting enzyme 2, is carboxypeptidase which converts angiotensin I to angiotensin 1-9, a peptide of unknown function, and angiotensin II to angiotensin 1-7, a vasodilator. It is able to hydrolyze apelin-13 and dynorphin-13 with high efficiency and may be an important regulator of heart function. Recombinant rat ACE2, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.