The localisation of 2-carboxy-D-arabinitol 1-phosphate and inhibition of Rubisco in leaves of Phaseolus vulgaris L.
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.
Biochemistry and Physiology Department, IACR-Rothamsted, Harpenden, UK. martin.parry@bbsrc.ac.uk
M A
MA
Parry
P J
PJ
Andralojc
H M
HM
Lowe
A J
AJ
Keys
D001665:Binding Sites; D002734:Chlorophyll / Q000032:analysis; D002736:Chloroplasts / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D007887:Fabaceae / Q000201:enzymology* / Q000378:metabolism; D005612:Freeze Drying; D008027:Light; D010428:Pentosephosphates / Q000378:metabolism*; D017440:Photoperiod; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism*; D010946:Plants, Medicinal; D012273:Ribulose-Bisphosphate Carboxylase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013431:Sulfates / Q000494:pharmacology; D013997:Time Factors
D004791:Enzyme Inhibitors; D010428:Pentosephosphates; D013431:Sulfates; C054549:2-carboxyarabinitol 1-phosphate; D002734:Chlorophyll; D012273:Ribulose-Bisphosphate Carboxylase