title: A re-investigation of the path of carbon in photosynthesis utilizing GC/MS methodology. Unequivocal verification of the participation of octulose phosphates in the pathway.
abstract: A GC/EIMS/SIM methodology has been developed to re-examine the path of carbon in photosynthesis. Exposing isolated spinach chloroplasts to 13CO2 on a solid support for a defined period followed by quenching and work-up provided a mixture of labelled sugar phosphates. After enzymatic dephosphorylation and derivatization, the Mox-TMS sugars were analysed using the above method. The purpose of the study was to try to calculate the atom% enrichment of 13C in as many of the individual carbons in each of the derivatized sugars as was practical using diagnostic fragment ions. In the event, only one 45 s experiment provided sufficient data to enable a range of enrichment values to be calculated. This confirmed that D-glycero-D-altro-octulose phosphate was present in the chloroplasts and was heavily labelled in the C4, C5 and C6 positions, in keeping with the hypothesis that it had an inclusive role and a labelling pattern consistent with a new modified pathway of carbon in photosynthesis.
authors.affiliation: Research School of Chemistry, Australian National University, Canberra, ACT, 0200, Australia.
authors.forename: Ian L
authors.initials: IL
authors.lastname: Flanigan
authors.forename: John K
authors.initials: JK
authors.lastname: MacLeod
authors.forename: John F
authors.initials: JF
authors.lastname: Williams
mesh_terms: D002138:Calibration; D002244:Carbon / Q000378:metabolism*; D002247:Carbon Isotopes; D002736:Chloroplasts / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D007661:Ketoses / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D018724:Spinacia oleracea / Q000378:metabolism*; D013403:Sugar Phosphates / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D007661:Ketoses; D013403:Sugar Phosphates; C022077:D-glycero-D-altro-octulose 1,8-bisphosphate; C022080:D-glycero-D-ido-octulose 1,8-bisphosphate; D002244:Carbon; D010100:Oxygen