Glucose phosphate plant

Since D-fructose and D-glucose phosphates are amongst the first products of photosynthesis, and since starch (in plants) and glycogen (in animals) are converted by phosphorylase to D-glucosyl phosphate, biosynthesis of carbohydrates revolves around these ubiquitous compounds... 

TAUBERGER, E., FERNIE, A.R., EMMERMANN, M., KOSSMANN, J., WILLMITZER, L., TRETHEWEY, R.N., Antisense inhibition of plastidial phosphoglucomutase provides compelling evidence that potato tuber amyloplasts import carbon from the cytosol in the form of glucose-6-phosphate, Plant J., 2000, 23, 43-53. 

Fu, Y, BalUcora, MA and Preiss, J. Mutagenesis of the glucose-1-phosphate binding site of potato tuber ADP-glucose pyrophosphorylase. Plant Physiol. 1998 117 989-996. 

Hayes, J.E., Simpson, R.J. and Richardson, A.E. (2000b) The growth and utilisation of plants in sterile media when supplied with inositol hexa-phosphate, glucose 1-phosphate or inorganic phosphate. Plant and Soil 220, 155-1 74. 

The monosaccharides found in living systems are mostly mono- and di-phosphate esters. Of greatest importance in animal metabolism are the three esters (10.11), which also occur in plant life, particularly fruit (Chapter 12.3). They have high water solubilities and high acid strengths (Table 5.26). Individual glucose phosphates vary greatly in their hydrolytic behaviour (Chapter 5.6). 

Because of the widespread occurrence of m /o-inositol in animals, plants, yeasts, molds, and bacteria, many attempts have been made at its synthesis. The chemical syntheses have been considered earlier in this chapter. Biochemical synthesis of inositol from n-glucose or D-glucose phosphate by action of a plant cyclase has been reported 126). The evidence for this transformation is a positive Scherer test there has been no definitive evidence in the form of isolation of myo-inositol. Evidence for synthesis in the animal body is based on the isolation of C Mabeled myo-inositol after the administration of C -labeled n-glucose 32h). 

Valuable information concerning the carbohydrates formed during steady state photosynthesis has been obtained by using cellulose chro matography in conjunction with radioactive carbon (29-32,57,58,235). During the flrst few seconds of photosynthesis there is concurrent formation of fructose and sedoheptulose phosphate followed by ketopentose phosphate and later by glucose phosphates (32,57). Examination of many plants shows sedoheptulose to be of widespread occurrence (31,192). 

C-labeled carbon dioxide is administered to a green plant, and shortly thereafter the following compounds are isolated from the plant 3-phosphoglycerate, glucose, erythrose-4-phosphate, sedoheptulose-l,7-bisphosphate, ribose-5-phosphate. In which carbon atoms will radioactivity be found ... 

In plant plastids, GGPP is formed from products of glycolysis and is eight enzymatic steps away from central glucose metabolism. The MEP pathway (reviewed in recent literature - ) operates in plastids in plants and is a preferred source (non-mevalonate) of phosphate-activated prenyl units (IPPs) for plastid iso-prenoid accumulation, such as the phytol tail of chlorophyll, the backbones of carotenoids, and the cores of monoterpenes such as menthol, hnalool, and iridoids, diterpenes such as taxadiene, and the side chains of bioactive prenylated terpenophe-nolics such as humulone, lupulone, and xanthohumol. The mevalonic pathway to IPP that operates in the cytoplasm is the source of the carbon chains in isoprenes such as the polyisoprene, rubber, and the sesquiterpenes such as caryophyllene. 

Lohmann118 detected an enzyme in muscle extracts, found later in plants and yeasts,104Co) 117,118 termed phosphoglucoisomerase, (optimum pH 9), which catalyzes the interconversion of D-glucose 6-phosphate (XVI) and D-fructose 6-phosphate (XVII). At equilibrium, which is attained rapidly, there is about 70 % of the former and 30 % of the latter. In a similar conver-... 

KAMMERER, B, FISHCER, K., HILPERT, B., SCHUBERT, S, GUTENSOHN, M., WEBER, A., FLUGGE, U.-I., Molecular characterization of a carbon transporter in plastids from heterotrophic tissues the glucose 6-phosphate phosphate antiporter, Plant Cell, 1998,10, 105-117. 

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