Title:Neutral endopeptidase neprilysin is copurified with Na,K-ATPase from rabbit outer medulla and hydrolyzes its alpha-subunit.
Authors:Groubman MA; Kamanina YV; Petrushanko IIu; Rubtsov AM; Lopina OD
Publication:Biochemistry (Mosc). 2010 Oct;75(10):1281-4.
Preparations of Na,K-ATPase from outer medulla of rabbit kidney purified in accordance with the method of P. L. Jorgensen were shown to contain as admixture a protease that moves with alpha-subunit (~100 kDa) as a single protein band during one-dimensional SDS-PAGE. The electro-elution of proteins of this band from polyacrylamide gel results in the appearance of two protein fragments (~67 and 55 kDa) that are stained with polyclonal antibodies against Na,K-ATPase alpha-subunit. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis showed that the neutral membrane-bound endopeptidase neprilysin is located in one protein band together with the Na,K-ATPase alpha-subunit. Addition of thiorphan, a specific inhibitor of neutral endopeptidase, eliminates proteolysis of the alpha-subunit. The data demonstrate that Na,K-ATPase alpha-subunit may be a natural target for neprilysin.