Development of Ribulose 1,5-Diphosphate Carboxylase in Nonphotosynthetic Endosperms of Germinating Castor Beans

Development of ribulose 1,5-diphosphate carboxylase in nonphotosynthetic endosperms of germinating castor beans.

Ribulose 1,5-diphosphate (RuDP) carboxylase has been partially purified from dark-grown nonphotosynthetic endosperms of germinating castor beans (Ricinus communis var. Hale). The Km values for RuDP, HCO(3) (-), and Mg(2+) are 0.51, 33, and 1.78 mm, respectively. The pH optimum for the carboxylation reaction is pH 7.5. Germination is required for the development of the carboxylase in the endospe...

The presence of ribulose 1,5-diphosphate carboxylase in the nonphotosynthetic endosperm of germinating castor beans.

Ribulose 1,5-diphosphate carboxylase was detected in extracts of germinating castor bean (Ricinus communis var. Hale) endosperms. This is the first report of this enzyme in a nonphotosynthetic (no chlorophyll) plant tissue. Radioactive 3-phosphoglyceric acid has been identified as the principle product resulting from the enzymatic condensation of (14)C-bicarbonate and ribulose-1,5-diP in endosp...

Development of ribulose-1,5-diphosphate carboxylase in castor bean cotyledons.

Light was not essential for the development of ribulose-1,5-diphosphate carboxylase protein or catalytic activity in the photosynthetic cotyledons of germinating castor beans (Ricinus communis). Cotyledons developing in the dark showed higher activity than those in the light. Returning cotyledons developing in the light to darkness resulted in a significant increase in ribulose-1,5-diphosphate ...

Ribulose Diphosphate Carboxylase / Oxygenase

The stimulation or inhibition of ribulose diphosphate oxygenase by a variety of compounds is compared with the reported effects on these compounds on the ribulose diphosphate carboxylase activity. A possible transition state analog of ribulose diphosphate, Z-carboxyribitol 1 ,5-diphosphate, at a molar ratio of inhibitor to enzyme of 10 to 1, irreversibly inactivates the oxygenase and carboxylas...

Ribulose Diphosphate Carboxylase in Thiorhodaceae.