scholarly journals Evidence for Effects on the in Vivo Activity of Ribulose-Bisphosphate Carboxylase/Oxygenase during Development of Mn Toxicity in Tobacco

1988 ◽  
Vol 86 (4) ◽  
pp. 1143-1149 ◽  
Author(s):  
Robert L. Houtz ◽  
Ross O. Nable ◽  
George M. Cheniae
Keyword(s):  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Bisphosphate Carboxylase ◽  
Mn Toxicity ◽  
Ribulose Bisphosphate Carboxylase Oxygenase

Immunolocalization of Rubisco Activase and Rubisco in C3 and C4 Plant Tissues

2000 ◽  
Vol 6 (S2) ◽  
pp. 472-473
Author(s):  
S. Madhavan ◽  
M. S. Miller-Goodman ◽  
K. W. Lee
Keyword(s):  
Higher Plants ◽  
Tight Binding ◽  
Rubisco Activase ◽  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate Carboxylase Oxygenase ◽  
Microscopic Studies ◽  
Sugar Phosphates

Ribulose bisphosphate carboxylase/oxygenase (Rubisco), an abundant enzyme in chloroplasts, must be activated by CO2 in order for it to catalyze the carboxylation of ribulose bisphosphate. Rubisco activase, a nuclear encoded chloroplast protein was first identified as a biochemical lesion in the rca mutant of Arabidopsis (1) which lacked this enzyme. Study of Rubisco in this mutant (2) and transgenic tobacco plants with reduced Rubisco activase levels showed that Rubisco could not achieve and maintain an adequate level of activity, in vivo, without an activase. Rubisco activase promotes ‘activation’ of Rubisco by overcoming the deleterious effects of tight binding sugar phosphates and low chloroplast CO2 levels on catalysis and carbamylation (1).Rubisco activase has been detected in higher plants (3), in unicellular green algae (4,5) and in cyanobacteria (6). Though the presence of Rubisco in guard cell chlroplasts was a subject of controversy, several immunolight and immunoelectron microscopic studies have demonstrated the presence of Rubisco in guard cells (7).

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