Presence of angiotensin-converting enzyme in follicular fluids of porcine ovaries and its possible involvement in the intrafollicular breakdown of bradykinin.
The follicular fluid of porcine ovaries contains a metalloenzyme capable of hydrolyzing the synthetic substrate, benzyloxycarbonyl-Val-Lys-Met-MCA. This enzyme was purified by ammonium sulfate fractionation followed by column chromatography on DEAE-cellulose, CM-cellulose, Zn(2+)-chelating Cellulofine, and Diol-300 gel-filtration columns. The molecular weight of the purified enzyme was estimated to be 170,000 by SDS-PAGE and 400,000 by gel-filtration analysis, suggesting that the native enzyme is a dimer of the 170-kDa subunit polypeptide. The enzyme activity was drastically enhanced by the presence of chloride ion, and strongly inhibited by captopril and bradykinin potentiator B. A 9-residue peptide containing a processing site of human amyloid precursor protein was degraded by its dipeptidyl carboxypeptidase activity. Furthermore, the purified protein was recognized by specific antibody raised against human angiotensin-converting enzyme. The enzyme rapidly degraded bradykinin in vitro. These results indicate that benzyloxycarbonyl-Val-Lys-Met-MCA-hydrolyzing enzyme is a porcine angiotensin-converting enzyme, and that the enzyme may play a role in bradykinin turnover within the follicles of porcine ovaries.
Matsui
Hitoshi
H
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Takahashi
Takayuki
T
D000818:Animals; D001920:Bradykinin / Q000378:metabolism*; D005260:Female; D015571:Follicular Fluid / Q000201:enzymology*; D006801:Humans; D006868:Hydrolysis; D010053:Ovary / Q000201:enzymology*; D007703:Peptidyl-Dipeptidase A / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D013552:Swine
D007703:Peptidyl-Dipeptidase A; D001920:Bradykinin