[Phe21]big endothelin-1(18-34) and [Ala31]big endothelin-1(18-34) inhibit the human endothelin-converting enzyme-1 (ECE-1) expressed in CHO-K1 cells in a different fashion.
Endothelin-converting enzyme-1 (ECE-1) is one of the most important enzymes to convert big endothelin-1 (big ET-1) to ET-1. To identify the inhibitors of ECE-1, we examined the effects of variously substituted analogues of big ET-1 on ECE-1 activity using solubilized membranes prepared from human ECE-1-expressed CHO-K1 cells. Among the big ET-1 analogues tested, [Phe21]big ET-1(18-34) and [Ala31]big ET-1(18-34) exhibited a significant inhibition of ECE-1. A kinetic analysis revealed [Phe21]big ET-1(18-34) to be a competitive inhibitor (Ki=20.6 microM) and [Ala31]big ET-1(18-34) to be a noncompetitive inhibitor (Ki=35.6 microM). These results not only support the concept that ECE-1 recognizes big ET-1 both at the P1 position and at the C-terminal region but also revealed that these two regions are recognized by this enzyme in a different manner.
Liu
W
W
The Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Takayanagi
R
R
Ito
T
T
Oba
K
K
Nawata
H
H
D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors* / Q000235:genetics; D016466:CHO Cells; D002462:Cell Membrane / Q000201:enzymology; D003001:Cloning, Molecular; D006224:Cricetinae; D019332:Endothelin-1 / Q000031:analogs & derivatives*; D000072396:Endothelin-Converting Enzymes; D016232:Endothelins / Q000494:pharmacology*; D004730:Endothelium, Vascular; D006801:Humans; D007700:Kinetics; D008666:Metalloendopeptidases; D011498:Protein Precursors / Q000494:pharmacology*; D014162:Transfection; D014471:Umbilical Veins
D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; C000606923:ECE1 protein, human; D000072396:Endothelin-Converting Enzymes