Sugar phosphates sucrose-6 -phosphate

After glucose synthesis in photosynthesis, the disaccharide sucrose (a-D-Glc(l —> 2)(3-D-Fru) is used as a readily transportable sugar. Sucrose synthesis successively involves the following UDP-glucose + fructose-6-phosphate —> sucrose-6-phosphate + UDP [via sucrose phosphate synthase] sucrose-6-phosphate + H20 —> sucrose + P [via sucrose-6-phosphatase]. 

Sucrose is ordinary table sugar.) To what volume should a solution containing 0.050 mol of each monosaccharide be diluted in order to bring about 5% conversion to sucrose phosphate ... 

PGA and the sugar phosphates clearly account for most of the found in individual compounds following a few seconds of photosynthesis with C 02. Nonetheless, one might ask whether or not other important pathways of CO2 reduction not involving these compounds have been overlooked. For example, there might be a pathway from CO2 to sucrose which does not include the intermediate compounds of the carbon reduction cycle. If so, this path would have to include substances which are so small in concentration as not to be seen, or which are so unstable as not to be isolated by the methods of paper chromatography. 

Glucose 6-phosphate was a prominent labeled component of the acid fraction at 2 min, before the appearance of free sugars. After this time, as the C content of free sugars increased, sucrose was the first free sugar to become labeled and at all times accounted for more than 90% of the C in this fraction. The labeling in free glucose and fructose showed that these compounds had originated from sucrose in a secondary reaction. 

It should be noted that isoprenoid biosynthesis requires acetyl-CoA, ATP, and NADPH. The physiological source of these compounds is presumably sugar phosphate metabolism, via glycolysis and the pentose phosphate pathway. We show sucrose as the starting material in Fig. 1, since it is the principal transport sugar in plants. Free acetate is not an important metabolite in plants acetyl-CoA is normally derived from pyruvate formed in glycolysis. Biosynthesis of terpenes implies that acetyl-CoA is diverted from the Krebs cycle and that the energy available from the Krebs cycle and oxidative phos-... 

The medium for the production of variotin, contained 3.0% sucrose, 0.2% dipotassium phosphate, 0.05% potassium chloride, 0.05% magnesium sulfate (hydrated), 0.001 % ferrous sulfate (hydrated), and 0.3 % sodium nitrate. Inorganic nitrogen sources were found to be more suitable for variotin production than organic nitrogen sources. Ammonium nitrate or ammonium sulfate could also be used. Of 11 sugars tested, sucrose was the most suitable carbon source for variotin formation (Takeuchi et al., 1959). The production of variotin reached a maximum by 4 or 5 days at 25 in shaken culture, or by 90 hours at 25 by aerated tank fermentation. 

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