Fructose 1,6-bisphosphate
Encyclopedia
Fructose 1,6-bisphosphate (also known as Harden-young ester) is fructose
Fructose
Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847...

 sugar phosphorylated on carbons 1 and 6 (i.e., is a fructosephosphate). The β-D-form of this compound is very common in cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

. The vast majority of glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

 and fructose entering a cell will become converted to fructose 1,6-biphosphate at some point.

Fructose 1,6-bisphosphate in glycolysis

Fructose 1,6-bisphosphate lies within the glycolysis
Glycolysis
Glycolysis is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+...

 metabolic pathway
Metabolic pathway
In biochemistry, metabolic pathways are series of chemical reactions occurring within a cell. In each pathway, a principal chemical is modified by a series of chemical reactions. Enzymes catalyze these reactions, and often require dietary minerals, vitamins, and other cofactors in order to function...

 and is produced by phosphorylation of fructose 6-phosphate
Fructose 6-phosphate
Fructose 6-phosphate is fructose sugar phosphorylated on carbon 6 . The β-D-form of this compound is very common in cells. The vast majority of glucose and fructose entering a cell will become converted to this at some point...

. It is, in turn, broken down into two compounds: glyceraldehyde 3-phosphate
Glyceraldehyde 3-phosphate
Glyceraldehyde 3-phosphate, also known as triose phosphate or 3-phosphoglyceraldehyde and abbreviated as G3P, GADP, GAP, TP, GALP or PGAL, is a chemical compound that occurs as an intermediate in several central metabolic pathways of all organisms...

 and dihydroxyacetone phosphate. It is an allosteric activator of pyruvate kinase
Pyruvate kinase
Pyruvate kinase is an enzyme involved in glycolysis. It catalyzes the transfer of a phosphate group from phosphoenolpyruvate to ADP, yielding one molecule of pyruvate and one molecule of ATP.-Reaction:The reaction with pyruvate kinase:...

.


The numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate.

Fructose 1,6-phosphate isomerism

Fructose 1,6-phosphate has only one biologically active isomer
Isomer
In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

, the β-D-form. There are many other isomers, analogous to those of fructose.

Iron Chelation

Fructose 1,6-bis(phosphate) has also been implicated in the ability to bind and sequester Fe(II), a soluble form of iron whose oxidation to the insoluble Fe(III) is capable of generating reactive oxygen species via Fenton chemistry. The ability of fructose 1,6-bis(phosphate) to bind Fe(II) may prevent such electron transfers, and thus act as an antioxidant within the body. Certain neurodegenerative diseases, like Alzheimer's
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

 and Parkinson's
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...

, have been linked to metal deposits with high iron content, although it is uncertain whether Fenton chemistry plays a substantial role in these diseases, or whether fructose 1,6-bis(phosphate) is capable of mitigating those effects.

See also

  • Fructose 2,6-bisphosphate
    Fructose 2,6-bisphosphate
    Fructose 2,6-bisphosphate abbreviated Fru-2,6-P2, is a metabolite that allosterically affects the activity of the enzymes phosphofructokinase 1 and fructose 1,6-bisphosphatase to regulate glycolysis and gluconeogenesis...

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