Lipoxygenase was extracted from Canola seeds (Brassica napus cv, Westar) and partially purified by precipitated with ammonium sulfate at 20-50% of saturation. The optimum pH for the enzyme activity was 7.5 and its K$ sb{ rm m}$ value was 2.0 $ times$ 10$ sp{-4}$ M. The activity of the enzyme extract was considerably greater on linoleic acid than on its ester or on linolenic acid. The effect of cyanide on the enzyme activity was also investigated. / Further purification of the enzyme extract was performed by successive chromatography on ion-exchange and gel filtration, using FPLC system. Four lipoxygenase isozymes (I, IIA, IIB and III) were separated. The homogeneity of each isozyme was demonstrated by the presence of a single protein band on SDS-PAGE gel electophoresis. The molecular weights of isozymes I, IIA, IIB and III were, respectively, 72,000, 106,000, 78,000 and 62,000. The optimum pH for lipoxygenase activity was 6.5 for isozyme I and 6.0 for isozymes IIA, IIB and III.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.59272 |
| Date | January 1990 |
| Creators | Khalyfa, Abdelnaby |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Food Science and Agricultural Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001070991, proquestno: AAIMM63471, Theses scanned by UMI/ProQuest. |
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