Abstract
A recent controversial report suggests that the nocturnal inhibitor of Rubisco, 2-carboxy-D-arabinitol 1-phosphate (CAIP), does not bind to Rubisco in vivo and therefore that CA1P has no physiological relevance to photosynthetic regulation. It is now proved that a direct rapid assay can be used to distinguish between Rubisco-bound and free CA1P, as postulated in the controversial report. Application of this direct assay demonstrates that CA1P is bound to Rubisco in vivo in dark-adapted leaves. Furthermore, CA1P is shown to be in the chloroplasts of mesophyll cells. Thus, CA1P does play a physiological role in the regulation of Rubisco.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Binding Sites
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Chlorophyll / analysis
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Chloroplasts / chemistry
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Chloroplasts / enzymology
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Chloroplasts / metabolism
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Enzyme Inhibitors / metabolism
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Fabaceae / enzymology*
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Fabaceae / metabolism
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Freeze Drying
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Light
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Pentosephosphates / metabolism*
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Photoperiod
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Plant Leaves / enzymology
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Plant Leaves / metabolism*
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Plants, Medicinal*
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Ribulose-Bisphosphate Carboxylase / antagonists & inhibitors*
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Ribulose-Bisphosphate Carboxylase / metabolism
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Sulfates / pharmacology
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Time Factors
Substances
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Enzyme Inhibitors
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Pentosephosphates
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Sulfates
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2-carboxyarabinitol 1-phosphate
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Chlorophyll
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Ribulose-Bisphosphate Carboxylase