Glucose conversion into fructose

Figure 4. Time course of glucose conversion into fructose using heat-treated glucose isomerase obtained from recombinant B. subtilis determined at 70 C and pH 7.0 using 35% (w/w) glucose solution and 10.8 units of enzyme/g of dry substance. Reprinted with permission from ref. 21. Copyright 1990 American Society for Microbiology.

The data show that SSHB increased the root dry matter in the same way it did in the other experiments. Simultaneously, we observed an increase in leaf length and leaf area which corresponded with an increase in invertase activity. The higher enzyme activity appeared to be the key to the whole problem. It is well known that acid invertase splits the disaccharide sucrose so that the two monosaccharides formed from it can become building stones for additional leaf substances. That is, glucose is recycled through the Embden-Meyerhof-Parnas pathway. Likewise, fructose is readily available for conversion into fructose 1,6-diphosphate. Subsequently, more leaf area arises which is able to produce more assimilates. The consequence is an increased yield. Thus, photosynthetic efficiency increases considerably. 

The conversion of the compounds under investigation into coloured derivatives (e.g., the separation of carbonyl compounds by conversion into their 2 4-dinitrophenylhydrazones, etc. of hydrocarbons through their picrates of alcohols through their 3 5-dinitrobenzoates of glucose, fructose and other simple sugars through their p-phenylazobenzoyl esters). 

The above-mentioned system is assumed to be involved in the conversion of glucose into fructose (H3, H5) according to the following reactions ... 

In homogeneous catalytic systems we witnessed a new process for the production of acetic acid from methanol and carbon monoxide using a transition metal complex, thus displacing the earlier process employing ethylene as the starting material. The use of immobilized enzymes makes possible the commercial conversion of glucose into fructose. 

Argument by analogy. Propose a mechanism for the conversion of glucose 6-phosphate into fructose 6-phosphate by phosphoglucose isomerase based on the mechanism of triose phosphate isomerase. 

Eurther conversion (saccharification) to dextrose can be done using glucoamylase. Starch consists of polymeric linear a-1,4 linked dextrose units (amylose, 25 % of the starch) and polymeric mixed a-l,4/a-l,6 linked dextrose units (amylopectin, 75 % of the starch). Eor enzymatic degradation besides a-1,4 specific amylases also a-1,6 specific amylases (pullulanases) are required. A portion of the dextrose can be converted into fructose with a glucose isomerase yielding a high fructose com symp (MFCS). 

Figure 9.7 shows the effect of a temperature decrease on the conversion of glucose into fructose. The first six cycles show the start-up period of the SMBR until cyclic steady state. At the end of the sixth cycle, the water temperature was reduced by... 

The conversion of fructose-1-phosphate into glycolytic intermediates bypasses two regulatory steps (the reactions catalyzed by hexokinase and PFK-1) thus fructose is metabolized more quickly than glucose. 

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