Abstract
It was examined where a protease purified from Vibrio cholerae might nick the heat-labile enterotoxin (LT) A subunit from enterotoxigenic Escherichia coli. LT was digested by the protease and contained a fragment which had the same mobility on SDS-PAGE as that of the A1 fragment of LT digested by trypsin. The biological activity of LT by this protease was also identical to that of LT by trypsin. The amino acid sequence of the N-terminus of the A2-like fragment was Thr-Ser-Thr-Gly, which corresponded to the sequence from 193 to 196 of the A subunit. These data suggest that this protease, like trypsin, nicks arginine at position 192 from the N-terminus of the A subunit and that the biological activation of LT by this protease is similar to that by trypsin.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Arginine / metabolism
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Bacterial Toxins / genetics
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Bacterial Toxins / isolation & purification
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Bacterial Toxins / metabolism*
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Electrophoresis, Polyacrylamide Gel
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Endopeptidases / isolation & purification
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Endopeptidases / metabolism*
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Enterotoxins / genetics
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Enterotoxins / isolation & purification
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Enterotoxins / metabolism*
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Escherichia coli / metabolism*
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Escherichia coli Proteins*
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Molecular Sequence Data
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Peptide Fragments / isolation & purification
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Peptide Fragments / metabolism
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Sodium Dodecyl Sulfate
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Trypsin / metabolism
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Vibrio cholerae / enzymology*
Substances
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Bacterial Toxins
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Enterotoxins
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Escherichia coli Proteins
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Peptide Fragments
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Sodium Dodecyl Sulfate
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Arginine
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heat-labile enterotoxin, E coli
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Endopeptidases
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Trypsin
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protease VC-I