New perspectives in the renin-angiotensin-aldosterone system (RAAS) I: Endogenous angiotensin converting enzyme (ACE) inhibition

Miklós Fagyas, Katalin Úri, Ivetta M. Siket, Andrea Daragó, Judit Boczán, Emese Bányai, I. Édes, Z. Papp, Attila Tóth

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Angiotensin-converting enzyme (ACE) inhibitors represent the fifth most often prescribed drugs. ACE inhibitors decrease 5-year mortality by approximately one-fifth in cardiovascular patients. Surprisingly, there are reports dating back to 1979 suggesting the existence of endogenous ACE inhibitors, which endogenous inhibitory effects are much less characterized than that for the clinically administered ACE inhibitors. Here we aimed to investigate this endogenous ACE inhibition in human sera. It was hypothesized that ACE activity is masked by an endogenous inhibitor, which dissociates from the ACE when its concentration decreases upon dilution. ACE activity was measured by FAPGG hydrolysis first. The specific (dilution corrected) enzyme activities significantly increased by dilution of human serum samples (23.2±0.7 U/L at 4-fold dilution, 51.4±0.3 U/L at 32-fold dilution, n =3, p = 0.001), suggesting the presence of an endogenous inhibitor. In accordance, specific enzyme activities did not changed by dilution when purified renal ACE was used, where no endogenous inhibitor was present (655±145 U/L, 605±42 U/L, n =3, p = 0.715, respectively). FAPGG conversion strongly correlated with angiotensin I conversion suggesting that this feature is not related to the artificial substrate. Serum samples were ultrafiltered to separate ACE (MW: 180 kDa) and the hypothesized inhibitor. Filtering through 50 kDa filters was without effect, while filtering through 100 kDa filters eliminated the inhibiting factor (ACE activity after

Original languageEnglish
Article numbere87843
JournalPLoS One
Volume9
Issue number4
DOIs
Publication statusPublished - Apr 1 2014

Fingerprint

Enzyme inhibition
angiotensins
renin
aldosterone
enzyme inhibition
peptidyl-dipeptidase A
Angiotensins
Peptidyl-Dipeptidase A
Renin-Angiotensin System
Aldosterone
Renin
Dilution
Enzyme activity
Angiotensin-Converting Enzyme Inhibitors
enzyme activity
Serum
angiotensin I
Filters (for fluids)
Angiotensin I
Enzymes

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

New perspectives in the renin-angiotensin-aldosterone system (RAAS) I : Endogenous angiotensin converting enzyme (ACE) inhibition. / Fagyas, Miklós; Úri, Katalin; Siket, Ivetta M.; Daragó, Andrea; Boczán, Judit; Bányai, Emese; Édes, I.; Papp, Z.; Tóth, Attila.

In: PLoS One, Vol. 9, No. 4, e87843, 01.04.2014.

Research output: Contribution to journalArticle

Fagyas, Miklós ; Úri, Katalin ; Siket, Ivetta M. ; Daragó, Andrea ; Boczán, Judit ; Bányai, Emese ; Édes, I. ; Papp, Z. ; Tóth, Attila. / New perspectives in the renin-angiotensin-aldosterone system (RAAS) I : Endogenous angiotensin converting enzyme (ACE) inhibition. In: PLoS One. 2014 ; Vol. 9, No. 4.
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