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Multiple forms of plant cytochromes p-450
1Department of Biological Sciences, The George Washington University, Washington, D.C. 20052.
Plant Physiology
|July 1, 1991
Summary
Plant cytochrome P-450 enzymes are diverse monooxygenases involved in metabolizing various compounds, including herbicides. These enzymes are crucial for plant defense and development, with multiple forms found across different cellular locations.
Area of Science:
- Plant biochemistry and molecular biology
- Enzymology and metabolic pathways
Background:
- Plants possess a diverse array of cytochrome P-450 enzymes, which are monooxygenases.
- These enzymes play critical roles in metabolizing endogenous compounds like sterols, terpenes, and gibberellins, as well as xenobiotics.
Purpose of the Study:
- To review the accumulating evidence for the multiplicity and functions of cytochrome P-450 enzymes in plants.
- To highlight their involvement in herbicide detoxification and the metabolism of various plant natural products.
Main Methods:
- Characterization of plant cytochromes P-450 through isolation and purification of specific enzymes.
- Reconstitution of purified cytochrome P-450 with NADPH:cytochrome P-450 reductase.
- Utilizing immunological techniques and specific inhibitors to study enzyme properties.
- Sequencing of a cytochrome P-450 demethylase to understand its structural features.
Main Results:
- Cytochromes P-450 are implicated in herbicide detoxification, evidenced by CO inhibition and requirement for O(2) and NADPH.
- Several plant cytochromes P-450 have been isolated, functioning as hydroxylases for various substrates.
- NADPH:cytochrome P-450 reductase acts as a general electron donor.
- Enzyme expression is regulated by external factors (wounding, pathogens) and occurs in specific cell types.
- Plant cytochromes P-450 are localized in diverse subcellular compartments.
Conclusions:
- Plant cytochrome P-450 systems are complex and multifaceted, involved in a wide range of metabolic processes.
- The diversity in subcellular localization suggests a large, yet unclassified, repertoire of plant cytochrome P-450 genes.
- Further research is needed to fully identify and classify the extensive family of plant cytochrome P-450 enzymes.
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