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Identification of prolyl carboxypeptidase as an alternative enzyme for processing of renal angiotensin II using mass spectrometry.
Pubmed ID: 23392115
Pubmed Central ID: PMC3651643
Journal: American journal of physiology. Cell physiology
Publication Date: May 15, 2013
Affiliation: Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, OH 45435, USA.
MeSH Terms: Male, Angiotensin-Converting Enzyme Inhibitors, Animals, Kidney, Peptide Fragments, Mice, Angiotensin I, Angiotensin II, Mice, Knockout, Carboxypeptidases, Dipeptides, Imidazoles, Leucine, Peptidyl-Dipeptidase A, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Angiotensin-Converting Enzyme 2
Grants: F32 DK093226, F32 DK-093226-01, F32 HL-105036, HL-051952, R01 DK039777, R01 HL-052779, R01 HL-093567, R21 HL-112666A, UL1 RR-033176, UL1 TR-000124, R01 HL110353, UL1 RR033176, P01 HL051952
Authors: Morris M, Grobe N, Schmaier AH, Weir NM, Leiva O, Ong FS, Bernstein KE, Elased KM
Cite As: Grobe N, Weir NM, Leiva O, Ong FS, Bernstein KE, Schmaier AH, Morris M, Elased KM. Identification of prolyl carboxypeptidase as an alternative enzyme for processing of renal angiotensin II using mass spectrometry. Am J Physiol Cell Physiol 2013 May 15;304(10):C945-53. Epub 2013 Feb 7.
Studies:
Abstract
Angiotensin-converting enzyme 2 (ACE2) catalyzes conversion of ANG II to ANG-(1-7). The present study uses newly established proteomic approaches and genetic mouse models to examine the contribution of alternative renal peptidases to ACE2-independent formation of ANG-(1-7). In situ and in vitro mass spectrometric characterization showed that substrate concentration and pH control renal ANG II processing. At pH ≥6, ANG-(1-7) formation was significantly reduced in ACE2 knockout (KO) mice. However, at pH <6, formation of ANG-(1-7) in ACE2 KO mice was similar to that in wild-type (WT) mice, suggesting alternative peptidases for renal ANG II processing. Furthermore, the dual prolyl carboxypeptidase (PCP)-prolyl endopeptidase (PEP) inhibitor Z-prolyl-prolinal reduced ANG-(1-7) formation in ACE2 KO mice, while the ACE2 inhibitor MLN-4760 had no effect. Unlike the ACE2 KO mice, ANG-(1-7) formation from ANG II in PEP KO mice was not different from that in WT mice at any tested pH. However, at pH 5, this reaction was significantly reduced in kidneys and urine of PCP-depleted mice. In conclusion, results suggest that ACE2 metabolizes ANG II in the kidney at neutral and basic pH, while PCP catalyzes the same reaction at acidic pH. This is the first report demonstrating that renal ANG-(1-7) formation from ANG II is independent of ACE2. Elucidation of ACE2-independent ANG-(1-7) production pathways may have clinically important implications in patients with metabolic and renal disease.