Biomaterial Database

Carbon isotope effect on carboxylation of ribulose bisphosphate catalyzed by ribulosebisphosphate carboxylase from Rhodospirillum rubrum. 1985

C A Roeske, and M H O'Leary

The carbon isotope effect at CO2 has been measured in the carboxylation of ribulose 1,5-bisphosphate by the ribulosebisphosphate carboxylase from Rhodospirillum rubrum. The isotope effect is obtained by comparing the isotopic composition of carbon 1 of the 3-phosphoglyceric acid formed in the reaction with that of the carbon dioxide source. A correction is made for carbon 1 of 3-phosphoglyceric acid which arises from carbon 3 of the starting ribulose bisphosphate. The isotope effect is k12/k13 = 1.0178 +/- 0.0008 at 25 degrees C, pH 7.8. This value is smaller than the corresponding value for the spinach enzyme. It appears that substrate addition with the R. rubrum enzyme is principally ordered, with ribulose bisphosphate binding first, whereas substrate addition is random with the spinach enzyme. The carboxylation step is partially rate limiting with both enzymes.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D002247	Carbon Isotopes	Stable carbon atoms that have the same atomic number as the element carbon but differ in atomic weight. C-13 is a stable carbon isotope.	Carbon Isotope,Isotope, Carbon,Isotopes, Carbon
D012247	Rhodospirillum rubrum	Vibrio- to spiral-shaped phototrophic bacteria found in stagnant water and mud exposed to light.
D012273	Ribulose-Bisphosphate Carboxylase	A carboxy-lyase that plays a key role in photosynthetic carbon assimilation in the CALVIN-BENSON CYCLE by catalyzing the formation of 3-phosphoglycerate from ribulose 1,5-biphosphate and CARBON DIOXIDE. It can also utilize OXYGEN as a substrate to catalyze the synthesis of 2-phosphoglycolate and 3-phosphoglycerate in a process referred to as photorespiration.	Carboxydismutase,Ribulose Biphosphate Carboxylase-Oxygenase,Ribulose Diphosphate Carboxylase,Ribulosebiphosphate Carboxylase,Rubisco,1,5-Biphosphate Carboxylase-Oxygenase,Ribulose Biphosphate Carboxylase,Ribulose Bisphosphate Carboxylase,Ribulose-1,5-Biphosphate Carboxylase,Ribulose-1,5-Biphosphate Carboxylase-Oxygenase,Ribulose-1,5-Bisphosphate Carboxylase Small-Subunit,Ribulose-Bisphosphate Carboxylase Large Subunit,Ribulose-Bisphosphate Carboxylase Small Subunit,Rubisco Small Subunit,1,5 Biphosphate Carboxylase Oxygenase,Biphosphate Carboxylase-Oxygenase, Ribulose,Carboxylase Small-Subunit, Ribulose-1,5-Bisphosphate,Carboxylase, Ribulose Bisphosphate,Carboxylase, Ribulose Diphosphate,Carboxylase, Ribulose-1,5-Biphosphate,Carboxylase, Ribulose-Bisphosphate,Carboxylase, Ribulosebiphosphate,Carboxylase-Oxygenase, 1,5-Biphosphate,Carboxylase-Oxygenase, Ribulose Biphosphate,Carboxylase-Oxygenase, Ribulose-1,5-Biphosphate,Diphosphate Carboxylase, Ribulose,Ribulose 1,5 Biphosphate Carboxylase,Ribulose 1,5 Biphosphate Carboxylase Oxygenase,Ribulose 1,5 Bisphosphate Carboxylase Small Subunit,Ribulose Biphosphate Carboxylase Oxygenase,Ribulose Bisphosphate Carboxylase Large Subunit,Ribulose Bisphosphate Carboxylase Small Subunit,Small Subunit, Rubisco,Small-Subunit, Ribulose-1,5-Bisphosphate Carboxylase
D012274	Ribulosephosphates	Ribulose substituted by one or more phosphoric acid moieties.