Abstract
A combination of HPLC elution patterns and peptide sequencing has been used to characterize two distinct activities present in subcellular fractions of bovine aortic endothelial cells (BAECs) capable of converting human big endothelin-1 (big ET-1) to mature (ET-1). A pepstatin-inhibitable activity with an acidic pH optimum present in a lysosome-enriched fraction cleaved big ET-1 at positions 18 and 21 at similar rates. A neutral pH activity present in a postlysosomal organelles subfraction was also able to convert big ET-1, and was inhibited by EDTA, but not by 1-chloro-3-tosylamido-4-phenyl-2-butanone (TPCK), an inhibitor of chymotrypsin-like serine proteases.
MeSH terms
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Animals
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Aspartic Acid Endopeptidases / antagonists & inhibitors
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Aspartic Acid Endopeptidases / metabolism*
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Cattle
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Chromatography, High Pressure Liquid
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Edetic Acid / pharmacology
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Endothelin-1
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Endothelin-Converting Enzymes
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Endothelins / metabolism*
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Endothelium, Vascular / enzymology*
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Freezing
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Hydrogen-Ion Concentration
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Metalloendopeptidases
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Pepstatins / pharmacology
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Protein Precursors / metabolism*
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Subcellular Fractions / enzymology
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Tosylphenylalanyl Chloromethyl Ketone / pharmacology
Substances
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Endothelin-1
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Endothelins
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Pepstatins
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Protein Precursors
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Streptomyces pepsin inhibitor
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Tosylphenylalanyl Chloromethyl Ketone
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Edetic Acid
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Aspartic Acid Endopeptidases
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Metalloendopeptidases
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Endothelin-Converting Enzymes
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pepstatin