Mass spectrometric determination of the inorganic carbon species assimilated by photoautotrophic cells of Euphorbia characias L

• Published in: The Journal of biological chemistry Vol. 263; no. 25; pp. 12373 - 12377
• Main Authors: Rebeille, F, Gans, P, Chagvardieff, P, Pean, M, Tapie, P, Thibault, P
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 05.09.1988; American Society for Biochemistry and Molecular Biology
• Subjects: Bicarbonates - metabolism; Biological and medical sciences; CARBON; Carbon - metabolism; CARBON DIOXIDE; Carbon Dioxide - metabolism; CARBONE; Carbonic Anhydrases - metabolism; CARBONO; CELL CULTURE; Cell structures and functions; Cells, Cultured; Chloroplast, photosynthetic membrane and photosynthesis; CULTIVO DE CELULAS; CULTURE DE CELLULES; DIOXIDO DE CARBONO; DIOXYDE DE CARBONE; EUPHORBIA; FOTOSINTESIS; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Kinetics; Mass Spectrometry; Molecular and cellular biology; PHOTOSYNTHESE; PHOTOSYNTHESIS; Plants - metabolism; Cell culture; Euphorbia; Dicotyledones; Angiospermae; Carbon dioxide; Euphorbiaceae; Spermatophyta; Kinetics; Gas exchange; Photosynthesis; Mass spectrometry; Uptake
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)37765-2

The chemical forms of inorganic carbon, CO2 or HCO3-, incorporated during photosynthesis in photoautotrophic Euphorbia characias cell suspension cultures were determined in experiments using 13CO2 and a mass spectrometry technique. From the equations of the CO2 hydration reaction, a kinetic model was first developed, and the effect of photosynthesis on the external CO2 concentration was simulated. It was predicted from this model that CO2 and HCO3- uptakes could be differentiated by recording only the CO2 variation rate in the external medium, successively in absence then in presence of an exogenous carbonic anhydrase activity. The results obtained with either CO2-grown or air-grown photoautotrophic cells were in good agreement with the model and demonstrated that CO2 was the sole species taken up during photosynthesis. In addition no accumulation of inorganic carbon within the cells was observed in the light. Similarly, in dark, CO2 was the only species released by respiration in the external medium.