A simple assay for the measurement of conversion of big endothelin-1 to endothelin-1 by smooth muscle.
The conversion of exogenous big endothelin-1 to endothelin-1 by the smooth muscle of denuded porcine coronary arterial strips was measured by radioimmunoassay. Repeated incubations of a porcine coronary arterial strip with the same concentration of big endothelin-1 yielded similar rates of conversion over a 4 h period. This property allowed the determination of a control rate of endothelin-1 conversion by a coronary arterial strip followed by measurement of rates under various conditions. The assay described in this report can be used to investigate the biochemical properties and inhibitor profiles of the extracellular enzyme mediating the conversion of big endothelin-1 to endothelin-1. The Km and Vmax of the enzyme were 34 +/- 2 microM and 88 +/- 8 fmol/min, respectively. Conversion of big endothelin-1 to endothelin-1 was optimal at pH 7.0 and was inhibited by classic metalloprotease inhibitors.
Balwierczak
J L
JL
Research Department, Ciba-Geigy Corp, Summit, NJ 07901.
Wong
M
M
Jeng
A Y
AY
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003331:Coronary Vessels / Q000378:metabolism; D019332:Endothelin-1; D016232:Endothelins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D011863:Radioimmunoassay; D013552:Swine
D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; D008666:Metalloendopeptidases