Sedoheptulose-l,7-bisphosphate

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 ... 

Beyond the classical glycolytic enzyme (See Aldolase), numerous enzymes catalyze aldol and aldol-like con-densation/cleavage reactions. Among them are the following (1) Sedoheptulose-l,7-bisphosphate aldolase, which converts sedoheptulose 1,7-bisphosphate to ery-throse 4-phosphate and dihydroxyacetone phosphate. 

Reaction 3 Transketolase transfers a 2-carbon unit sedoheptulose-l,7-bisphosphate ->sedoheptulose-7-phosphate... 

Sedoheptulose-l,7-Bisphosphate + H2O <=> Sedoheptulose-7-Phosphate + Pi Enzyme = Sedoheptulose-1,7-... 

Erythrose-4-Phosphate + Dihydroxy acetone Phosphate <=> Sedoheptulose-l,7-Bisphosphate... 

Some of the many differences include the involvement of erythrose-4-phosphate and dihydroxyacetone phosphate in the production of sedoheptulose-1,7-bisphosphate, phosphorylation of ribulose-5-phos-phate to ribulose-l,5-bisphosphate, the addition of C02 to ribulose-l,5-bisphosphate, and the production of two glyceraldehyde-3-phosphates. 

Despite the fact that many heptoses are by far less prominent in Nature than hexoses these monosaccharides are found both as metabolic intermediates, and as structural carbohydrates of bacterial cell walls.D-Sedoheptulose 7-phosphate is an important intermediate of the pentose cycle, and D-sedoheptulose 1,7-bisphosphate is present in plants as an intermediate of the dark phase of photosynthetic reactions. L-Glycero-D-manno-heptose was isolated from the oligosaccharides obtained by partial acid hydrolysis of the lipopolysaccharide from Escherichia coli K-12 strain W3100 [153] and Haemophilus influenzae [154]. Both L-glycero-D-wtanno-heptose and D-glycero-D-ma o-heptose were isolated from the lipopolysaccharide of Vibrio parahaemolyticus [155]. 

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