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Characterization of nucleoside triphosphatase activity in isolated pea nuclei and its photoreversible regulation by lightA nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the hydrolysis of ATP, GTP, UTP, and CTP, all with a pH optimum of 7.5. The nuclear NTPase activity was not inhibited by vanadate, oligomycin, or nitrate, but was inhibited by relatively low concentrations of quercetin and the calmodulin inhibitor, compound 48/80. The NTPase was stimulated more than 50% by red light, and this effect was reversed by subsequent irradiation with far-red light. The photoreversibility of the stimulation indicated that the photoreceptor for this response was phytochrome, an important regulator of photomorphogenesis and gene expression in plants.
Document ID
20040089992
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Chen, Y. R.
(University of Texas at Austin 78713 United States)
Roux, S. J.
Date Acquired
August 21, 2013
Publication Date
January 1, 1986
Publication Information
Publication: Plant physiology
Volume: 81
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NSG 7480
CONTRACT_GRANT: PCM 8402526
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center

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