In vitro studies of dark (14)CO(2) fixation with isolated cell aggregates of Kalanchoë fedtschenkoi showed that malate synthesized after 20 sec is predominantly (85 to 92%) labeled at carbon 4, while after 20 min only 65 to 69% of the radioactivity was located in this position. The intramolecular labeling pattern of malate could not be changed by supplementing the cells with carboxylation react...

Recent investigations in this laboratory have shownl 2 that the isocitrate(or citrate-) activated form of liver acetyl CoA carboxylase (E.C. 6.4.1.2) is a large protein structure having a molecular weight of about four million. Electron microscopic examination of the carboxylase in the presence of isocitrate reveals' that it has a filamentous structure with dimensions of SG-100 A by up to 5000 ...

A novel framework is presented for the analysis of ecophysiological field measurements and modelling. The hypothesis 'leaves minimise the summed unit costs of transpiration and carboxylation' predicts leaf-internal/ambient CO2 ratios (ci /ca ) and slopes of maximum carboxylation rate (Vcmax ) or leaf nitrogen (Narea ) vs. stomatal conductance. Analysis of data on woody species from contrasting ...

Photo-catalyzed tandem dearomatization/carboxylation of benzyl o-halogenated aryl ether with CO2 was achieved, which affords spirocyclic carboxylic acids under mild conditions. The reaction has good functional group tolerance high yields. Mechanism studies indicate that the transformation realized via intramolecular radical addition and nucleophilic addition.

A Ni-catalyzed reductive carboxylation of N-substituted aziridines with CO2 at atmospheric pressure is disclosed. The protocol characterized by its mild conditions, experimental ease, and exquisite chemo- regioselectivity pattern, thus unlocking a new catalytic blueprint to access ?-amino acids, important building blocks considerable potential as peptidomimetics.