Novel Variants of Angiotensin Converting Enzyme-2 of Shorter Molecular Size to Target the Kidney Renin Angiotensin System

Wysocki, Jan; Schulze, Arndt; Batlle, Daniel

In mouse urine, two ACE2-immunoreactive bands are present [12] . In fresh kidney lysates, however, only a 100-110 kD ACE2 band was found to be consistent with the molecular size of native mouse ACE2 [12] . It was unclear whether the lower 75 kD band was a product of native ACE2 degradation or a distinct protein. We therefore decided to examine the possibility that the 75 kD band could be a proteolytic digestion product of the 110 kD ACE2 band. To study the hypothesis of ACE2 proteolysis, urines and kidneys from ACE2-deficient mice were spiked with native mrACE2 that we had generated, over-expressed and purified. This native recombinant mouse (mr)ACE2 has a molecular size of 100-110 kD (740 amino acid long) and contains a poly-His tag on its C-terminus [7] . Samples from ACE2 knockout mice were used to eliminate any interference arising from endogenous ACE2.