Analysis of big endothelin-1 digestion by cathepsin D.
Digestion of big endothelin (ET)-1 by cathepsin D, which is the only substantially identified protease showing ET converting enzyme activity, was characterized. Increased doses of cathepsin D showed decrease of immunoreactive (ir-) ET produced from big ET-1. Time course of big ET-1 conversion showed marked increase of ir-ET in a relatively short period, but further incubation resulted in the decrease of ir-ET. Incubation at various pHs with different doses of cathepsin D revealed that low doses of cathepsin D yielded the maximum production of ir-ET at pH 3.5-4.0, but higher doses of cathepsin D showed a bimodal curve of ir-ET production, which may be due to degradation of ir-ET. HPLC analysis revealed that cathepsin D cleaves Asn18-Ile19 bond in addition to Trp21-Val22 bond of big ET-1. These data suggests cathepsin D is not a physiological endothelin converting enzyme.
Sawamura
T
T
Department of Biochemistry, University of Tsukuba, Ibaraki, Japan.
Shinmi
O
O
Kishi
N
N
Sugita
Y
Y
Yanagisawa
M
M
Goto
K
K
Masaki
T
T
Kimura
S
S
D000595:Amino Acid Sequence; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D002402:Cathepsin D / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D019332:Endothelin-1; D000072396:Endothelin-Converting Enzymes; D016232:Endothelins / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008666:Metalloendopeptidases; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D011498:Protein Precursors / Q000378:metabolism*; D011863:Radioimmunoassay; D013379:Substrate Specificity
D019332:Endothelin-1; D016232:Endothelins; D010446:Peptide Fragments; D011498:Protein Precursors; D016282:Aspartic Acid Endopeptidases; D002402:Cathepsin D; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes