The single residue of cysteine in Cl. botulinum type E strain Iwanai toxin has been linked with toxicity, by chemical modification using p-chloromercuribenzoate.
A peptide containing the oysteine residue has been isolated by exhaustive tryptic digestion of the toxin molecule tagged with N-(4-dimethylamino-3,5-dinitrophenyl) maleimide, and subsequent gel filtration with Sephadex G-25 and descending paper chromatography.
The toxic peptide of trypsin-activated toxin was isolated by fractionation through a composite Sephadex G-75 and G-50 column.
By chymotryptic and tryptic digestion of the toxin at pH 5.8, a toxic fragment has been isolated by gel filtration with Sephadex G-25.
On the basis of quantitative amino acid analyses, the molecular weights of the intact toxin, the trypsin-activated toxin and the chymotrypsin-trypsin fragmented toxin have been estimated to be 14,000-16,000, 10,000-12,000 and 4,000-6,000 respectively.
Although the mechanism of tryptic activation was found to involve chiefly the removal of at least 18 amino acid residues from the N-terminus of the toxin molecule, the manner of reduction by cleavage has not been determined for the chymotrypsin-trypsin fragmented toxin. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/38660 |
| Date | January 1965 |
| Creators | Ko, Arthur S.C. |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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