In this study, two symbiotic fungi of Southern Pine Beetle (SPB),
Entomocorticium peryii and Entomocorticium sp.A were evaluated in terms of
polyphenol oxidase (PPO) production. The effect of different inhibitors, inducers and
assay parameters such as temperature and pH on enzyme activity were investigated
and maximum PPO activity was observed at 30° / C, pH 8.0 and when tannic acid was
used as an inducer. Copper-chelator salicyl hydroxamic acid (SHAM) and pcoumaric
acid, both indicated as inhibitors of tyrosinase and catechol oxidase
significantly reduced the activity.
For biochemical characterization studies, the enzyme was concentrated by
ultrafiltration. To determine type of the enzyme, activity staining after Native-PAGE
was carried out. Type of polyphenol oxidase produced by E. peryii and E. sp.A was
determined as catechol oxidase by activity staining. However higher activity was
observed on hydroquinone (p-diphenol) rather than catechol (o-diphenol).
The enzyme obeys Michealis-Menten kinetics with Km and Vmaxvalues being 10.72 mM hydroquinone and 59.44 U/ml for E. peryii and 8.55 mM hydroquinone and 73.72 U/ml for E. sp.A respectively..
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12608217/index.pdf |
| Date | 01 February 2007 |
| Creators | Valiev, Abduvali |
| Contributors | Ogel, Zumrut Begum |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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