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Regulation of angiotensin I‐converting enzyme in cultured bovine bronchial epithelial cells
Author(s) -
Müns Günther,
Vishwanatha Jamboor K.,
Rubinstein Israel
Publication year - 1993
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240530413
Subject(s) - captopril , western blot , enzyme , angiotensin converting enzyme , chemistry , enzyme assay , microbiology and biotechnology , biochemistry , endocrinology , biology , blood pressure , gene
The purpose of this study was to determine whether angiotensin I‐converting enzyme (ACE) is present in cultured bovine bronchial epithelial cells (BBECs) and whether its activity can be modulated. We found that extracts of confluent monolayers of cultured BBECs degraded [glycine‐1‐ 14 C]hippuryl‐ L ‐histidyl‐ L ‐leucine at a rate of 843 ± 66 pmol/hr/mg protein (mean ± SEM, n = 5). In addition, we found that the enzyme was shed into the culture medium. ACE activity in BBECs was inhibited by three selective, but structurally different, ACE inhibitors (captopril, quinapril, and cisalaprilat) with an IC 50 of approximately 2 nM. Increasing chloride concentration in the assay buffer resulted in an increase in BBECs ACE activity of 63%. Enzyme activity was also modulated by the presence of zinc cation in the assay buffer. Addition of dexamethasone to the culture medium was associated with a significant increase in BBECs ACE activity ( P < 0.05), which was inhibited by the steroid receptor antagonist RU 38486. Western blot analysis of BBECs, tracheal and bronchial mucosal strips utilizing a cross‐reacting rabbit anti‐mouse ACE antibody, showed a faint 175 kDa band and additional strong 52 kDa and 47 kDa band. The mechanism of generation of the low M.W. bands is unknown. Our data indicate the presence of ACE in cultured BBECs and that enzyme activity can be modulated.