Fructose-6-phosphate
Fructose-6-phosphate is one of the metabolites of the carbohydrates metabolism pathway, which has glucose-6-phosphate as a precursor and fructose-1,6-biphosphate as a postcursor . More specifically, it is found in the glycolysis stage of the carbohydrates metabolism.
Production of fructose-6-phosphate from glucose-6-phosphate
Fructose-6-phosphate results from a aldopyranose to ketofuranose conversion which involves a sequence of events. These events are catalysed by phosphoglucose isomerase. The first one is a conversion from the ring form of glucose-6-phosphate to the linear form. The second one is the conversion from this linear form to a linear ketohexose form by a nucelophilic attack of the double bonded oxygen atom on the first carbon atom. Then, the linear ketohexose is converted to its ring form by carbon 2 binding covalently to the oxygen atom on carbon 5.
Conversion of fructose-6-phosphate to fructose-1,6-biphosphate
This conversion involves an enzyme called phosphofructokinase. It phosphorylates carbon 1 of fructose-6-phosphate by adding a phosphate group from ATP. The process involves the ATP forming a complex with Mg2+ in which the ion neutralises the charges of the alpha and beta phosphoryl groups of ATP .This way, only the gamma phosphoryl group of ATP is used for phosphorylation.<span style="font-size: 11.0667px;" />