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Hydrogen peroxide homeostasis: activation of plant catalase by calcium/calmodulinEnvironmental stimuli such as UV, pathogen attack, and gravity can induce rapid changes in hydrogen peroxide (H(2)O(2)) levels, leading to a variety of physiological responses in plants. Catalase, which is involved in the degradation of H(2)O(2) into water and oxygen, is the major H(2)O(2)-scavenging enzyme in all aerobic organisms. A close interaction exists between intracellular H(2)O(2) and cytosolic calcium in response to biotic and abiotic stresses. Studies indicate that an increase in cytosolic calcium boosts the generation of H(2)O(2). Here we report that calmodulin (CaM), a ubiquitous calcium-binding protein, binds to and activates some plant catalases in the presence of calcium, but calcium/CaM does not have any effect on bacterial, fungal, bovine, or human catalase. These results document that calcium/CaM can down-regulate H(2)O(2) levels in plants by stimulating the catalytic activity of plant catalase. Furthermore, these results provide evidence indicating that calcium has dual functions in regulating H(2)O(2) homeostasis, which in turn influences redox signaling in response to environmental signals in plants.
Document ID
20040088413
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Yang, T. (Washington State University Pullman, WA 99164-6414, United States)
Poovaiah, B. W.
Date Acquired
August 21, 2013
Publication Date
March 19, 2002
Publication Information
Publication: Proceedings of the National Academy of Sciences of the United States of America
Volume: 99
Issue: 6
ISSN: 0027-8424
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center