Angiotensin-converting enzyme in pericardial fluid: comparative study with serum activity.
Arq Bras Cardiol
; 91(3): 156-61, 172-8, 2008 Sep.
Article
em En, Pt
| MEDLINE
| ID: mdl-18853057
ABSTRACT
BACKGROUND:
The characterization of an angiotensin-converting enzyme (ACE) in human pericardial fluid is relevant, considering its role in the angiotensin II release and thus, the role of the pericardium in cardiovascular homeostasis.OBJECTIVE:
To isolate and characterize an ACE from human pericardial fluid and to compare the angiotensin I converting activities of the pericardial fluid with that of the serum in patients submitted to cardiovascular surgery.METHODS:
The enzyme from human pericardial fluid was purified through chromatographic steps and characterized by polyacrylamide gel electrophoresis (SDS-PAGE), hydrolysis of angiotensin I, bradykinin, Hip-His-Leu and synthetic substrates with internal fluorescence suppression. Lisinopril was used as inhibitor. The ACE activity was measured in blood and pericardial fluid samples of 23 patients submitted to cardiovascular surgery.RESULTS:
The purified ACE (MM = 140 kDa), releases angiotensin II, hydrolyses bradykinin and the Hip-His-Leu substrate. The kinetic parameters k cat,(s-1) and k cat/Km (microM-1. s-1) were, respectively Hip-His-Leu (1.14 and 7 x 10 -4) ; Abz-YRK(Dnp)P-OH (2.60 and 0.77), Abz-LFK(Dnp)-OH (2.77 and 0.36) and Abz-SDK(Dnp)P-OH (1.92 and 0.19). The angiotensin I converting activities (mean +/- SD) in the pericardial fluid and in blood, were, respectively 3.16 +/- 0.90 mU x mg -1x min-1 and 0.33 +/- 0.11 mU x mg -1x min-1. The difference was significant between the two fluids.CONCLUSION:
An ACE that bears great similarity with the somatic enzyme was isolated from human pericardial fluid. The angiotensin I converting activity is higher in the pericardial fluid when compared to the serum activity. These data are important evidence of the role of the pericardial fluid in the metabolism of active peptides.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Derrame Pericárdico
/
Doenças Cardiovasculares
/
Peptidil Dipeptidase A
Limite:
Humans
Idioma:
En
/
Pt
Revista:
Arq Bras Cardiol
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Brasil