Localization of carboxypeptidase A-like enzyme in rat kidney.
In this study we demonstrate that carboxypeptidase A (CPA)-like enzyme is expressed in rat kidney. The major metabolites of angiotensin (Ang) I by the rat renal mesangial cell extract at 37 degrees C, pH 7.4, were Ang 1-9 and Ang II. Quinaprilat did not influence the formation of Ang 1-9, but it inhibited formation of Ang II. The formation of Ang 1-9 was inhibited by potato carboxypeptidase inhibitor, 1,10-phenanthroline or EDTA. Lowering the pH from 7.4 to 4.0 also inhibited the formation of this nonapeptide. These findings suggest that a metallocarboxypeptidase is responsible for Ang 1-9 production. Using monoclonal antibodies to CPA, Western blot showed the presence of CPA-like enzyme in the extracts prepared from the mesangial cells or kidney cortex of the rat. Immunohistochemistry showed that CPA-like enzyme is localized in the mesangial glomerular cells and adventitia of kidney blood vessels, whereas it was absent in the renal tubules. Our data suggest that a CPA-like enzyme could be added to a repertoire of enzymes present in the rat mesangial cells and adventitia of renal blood vessels.
Igić
Rajko
R
Department of Anesthesiology and Pain Management, Room 427DX, 637 S. Wood Street, Chicago, IL 60612 , USA. rigic@hektoen.org
Garber
Sandra
S
Sekosan
Marin
M
Urbanska
Renata A
RA
Behnia
Rahim
R
D000803:Angiotensin I / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D043422:Carboxypeptidases A / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D051381:Rats
D010446:Peptide Fragments; D010455:Peptides; D000804:Angiotensin II; D000803:Angiotensin I; D043422:Carboxypeptidases A; C118790:angiotensin I (1-7)