We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Cell wall peroxidases in the liverwort Dumortiera hirsuta are responsible for extracellular superoxide production, and can display tyrosinase activity.
- Authors
Li, Jackson L. Y.; Sulaiman, Mariam; Beckett, Richard P.; Minibayeva, Farida V.
- Abstract
In our earlier work, we showed that the liverwort Dumortiera hirsuta produces an extracellular oxidative burst of superoxide radicals during rehydration following desiccation stress. The oxidative burst is a common early response of organisms to biotic and abiotic stresses, with suggested roles in signal transduction, formation of protective substances such as suberin, melanin and lignin and defense against pathogens. To discover which enzymes are responsible for the extracellular superoxide production, we isolated apoplastic fractions from D. hirsuta, surveyed for the presence of potential redox enzymes, and performed non-denaturing polyacrylamide gel electrophoresis activity stains. Various isoforms of peroxidase (EC 1.11.1.7) and tyrosinase ( o-diphenolase) (EC 1.10.3.1) were present at significant levels in the apoplast. In-gel activity staining revealed that some peroxidases isoforms could produce superoxide, while tryosinases could readily metabolize 3,4-dihydroxy phenyll-alanine (l-dopa) into melanins. Interestingly, some peroxidase isoforms could oxidize the native tyrosinase substratel-dopa at significant levels, even in the absence of hydrogen peroxide, while others could do so only in the presence of hydrogen peroxide. In D. hirsuta, peroxidases may play an important role in melanin formation. Possible functions for these diverse oxidases in liverwort biology are discussed.
- Subjects
PLANT cell walls; PEROXIDASE; LIVERWORTS; SUPEROXIDES; PHENOL oxidase; CELLULAR signal transduction; LIGNINS; PATHOGENIC microorganisms; POLYACRYLAMIDE gel electrophoresis; HYDROGEN peroxide; DUMORTIERA hirsuta
- Publication
Physiologia Plantarum, 2010, Vol 138, Issue 4, p474
- ISSN
0031-9317
- Publication type
Article
- DOI
10.1111/j.1399-3054.2009.01318.x