The Active Species of “CO2” Utilized by Ribulose Diphosphate Carboxylase

Autotrophic CO2 assimilation and the evolution of ribulose diphosphate carboxylase.

From Heterotrophism to Autotrophism .......... ............................... 299 New Catalysts in CO.-Fixing Autotrophs ......... .............................. 300 RuDP carboxylase and phosphoribulokinase ....... .......................... 300 Properties of RuDP Carboxylase............................................... 300 Kinetic response to substrates ........................................

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.

The carboxylation of phosphoenolpyruvate and pyruvate. II. The active species of "CO2" utilized by phosphoenlpyruvate carboxylase and pyruvate carboxylase.

The active species of “COP,” i.e. CO2 or HCO,, utilized in the pyruvate carboxylase and phosphoenolypruvate carboxylase reaction have been determined with an assay predicated upon the fact that the hydration of CO2 is a kinetically slow and measurable reaction. The results of these assays in both cases are in reasonable agreement with those expected if HCOIis assumed to be the functional specie...

Inhibition of ribulose 1,5-diphosphate carboxylase by 6-phosphogluconate.

6-Phosphogluconate is a much more effective inhibitor of the photosynthetic carboxylation enzyme, ribulose-1, 5-diphosphate carboxylase, than other sugar phosphates and sugar acids of the reductive and oxidative pentose phosphate cycles. The inhibition appears to be noncompetitive with ribulose 1,5-diphosphate. Since 6-phosphogluconate is unique to the oxidative cycle and inhibits at concentrat...