A dissertation submitted to the School of Molecular and Cell Biology, Faculty of Science,
University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the
degree of Master of Science.
Johannesburg, 2015 / Cyanogenesis is defined as the hydroxynitrile lyase catalysed release of a cyanide
group in the form of hydrogen cyanide and the corresponding aldehyde or ketone.
When a plant is attacked, the hydrogen cyanide released is a self-defence mechanism.
A special characteristic of enzymatic reactions is that all enzymatic reactions are
reversible - hydroxynitrile lyases can also be used for the synthesis of
enantiomerically pure cyanohydrins which are of great importance in industry. In this
study, the hydroxynitrile lyase activity of 102 plants from 41 families was
investigated, first by screening for cyanogenic activity, followed by a hydroxynitrile
lyase activity assay. Six plants were found to be cyanogenic and exhibited specific
hydroxynitrile lyase activity: Adenia sp. (0.44 U/mg), Adenia firingalavensis (2.88
U/mg), Adenia fruticosa (1.99 U/mg), Adenia pechuelii (2.35 U/mg), Heywoodia
lucens (1.76 U/mg) and Ximenia caffra (1.84 U/mg). This is the first report of
hydroxynitrile lyase activity in these plants.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/19342 |
| Date | 19 January 2016 |
| Creators | Kassim, Muhammad Arshad |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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