{{Short description|Class of chemical compounds}} '''Fructose phosphates''' are sugar phosphates based upon fructose, and are common in the biochemistry of cells.<ref>{{cite journal|pmid=4312415|year = 1969|last1 = Dikow|first1 = A. L|title = Biochemical and histochemical studies of fructosephosphate aldolase in tumors of the nervous system. Isoenzymes of fructosephosphate aldolase. 8|journal = Zeitschrift für klinische Chemie und klinische Biochemie|volume = 7|issue = 6|pages = 606–13|last2 = Lolova|first2 = I|last3 = Ivanova|first3 = A|last4 = Bojinov|first4 = S}}</ref> A fructose phosphate is formed when fructose is phosphorylated through the addition of an inorganic phosphate group (P<sub>i</sub>).
Fructose is a naturally occurring monosaccharide and is referred to as a "fruit sugar" due to existing in virtually every fruit.<ref>{{Citation |last1=Shintani |first1=Tomoya |title=The Sugars with the Potential to Prolong Human Life |date=2021-09-01 |work=Sugar Intake - Risks and Benefits and the Global Diabetes Epidemic |editor-last=James Martins |editor-first=Ian |url=https://openresearchlibrary.org/ext/api/media/edad5eb1-41ca-4982-b831-ced5b4525c24/assets/external_content.pdf |access-date=2025-05-05 |publisher=IntechOpen |language=en |doi=10.5772/intechopen.97885 |isbn=978-1-83881-121-1 |last2=Lema-Perez |first2=Laura |last3=Shintani |first3=Hideya}}</ref> Fructose is a six-carbon molecule and can be drawn as a linear chain (Fischer Projection) or a ring-like structure (Haworth Projection), consisting of carbon and hydroxyl groups. Inorganic phosphate is an anion that plays a fundamental role in various key biological processes.<ref>{{Citation |last=Mustaev |first=Arkady |title=Inorganic Phosphate: The Backbone of Life |date=2023-06-21 |work=Functional Phosphate Materials and Their Applications |editor-last=Ameen |editor-first=Sadia |url=https://www.intechopen.com/chapters/85667 |access-date=2025-05-05 |publisher=IntechOpen |language=en |doi=10.5772/intechopen.109117 |isbn=978-1-80356-800-3 |editor2-last=Shaheer Akhtar |editor2-first=Mohammad |editor3-last=Shin |editor3-first=Hyung-Shik|doi-access=free }}</ref>
Fructose phosphates play integral roles in many metabolic pathways, particularly glycolysis, gluconeogenesis, oxidative phosphorylation, and lipogenesis.<ref>{{Cite journal |last1=Sun |first1=Sam Z |last2=Empie |first2=Mark W |date=2012 |title=Fructose metabolism in humans – what isotopic tracer studies tell us |journal=Nutrition & Metabolism |language=en |volume=9 |issue=1 |page=89 |doi=10.1186/1743-7075-9-89 |doi-access=free |issn=1743-7075 |pmc=3533803 |pmid=23031075}}</ref> Furthermore, biomedical research has increasingly demonstrated the role of fructose phosphates in metabolic processes and how dysregulation of their production or metabolism can contribute to several human diseases.<ref name=":1">{{Cite journal |last1=Hannou |first1=Sarah A. |last2=Haslam |first2=Danielle E. |last3=McKeown |first3=Nicola M. |last4=Herman |first4=Mark A. |date=2018-02-01 |title=Fructose metabolism and metabolic disease |journal=Journal of Clinical Investigation |language=en |volume=128 |issue=2 |pages=545–555 |doi=10.1172/JCI96702 |issn=0021-9738 |pmc=5785258 |pmid=29388924}}</ref>
== Role in Metabolism == Fructose phosphorylation and dephosphorylation events involve specific enzymes that either add or remove phosphate groups depending on the cellular context. All known enzymatic phosphorylations of fructose (i.e., hexokinase, fructokinase, or phosphofructokinase-1) are ATP-dependent.<ref name=":0">{{Cite journal |last1=Hue |first1=L. |last2=Rider |first2=M. H. |date=1987-07-15 |title=Role of fructose 2,6-bisphosphate in the control of glycolysis in mammalian tissues |journal=The Biochemical Journal |volume=245 |issue=2 |pages=313–324 |doi=10.1042/bj2450313 |issn=0264-6021 |pmc=1148124 |pmid=2822019}}</ref> All of these enzymes use Adenosine Triphosphate (ATP) as the phosphate donor to transfer the γ-phosphate to fructose or fructose-derivatives under normal physiological conditions.<ref>{{Cite journal |last1=Furuya |first1=E |last2=Yokoyama |first2=M |last3=Uyeda |first3=K |date=January 15, 1982 |title=Regulation of fructose-6-phosphate 2-kinase by phosphorylation and dephosphorylation: possible mechanism for coordinated control of glycolysis and glycogenolysis. |journal=Proceedings of the National Academy of Sciences |language=en |volume=79 |issue=2 |pages=325–329 |doi=10.1073/pnas.79.2.325 |doi-access=free |issn=0027-8424 |pmc=345719 |pmid=6281764 |bibcode=1982PNAS...79..325F }}</ref> On the other hand, dephosphorylation reactions of fructose are not ATP-dependent, but rather are hydrolytic and catalyzed by phosphatases (e.g., fructose 1,6-bisphosphatase, fructose 2,6-bisphosphatase, or phosphoprotein phosphatase).<ref name=":0" /> Furthermore, these reactions do not require ATP due to being energetically favorable, and thus, use water to cleave the phosphate ester bond and release a P<sub>i</sub>.
Examples of major biologically active fructose phosphates are: *Fructose 1-phosphate *Fructose 2-phosphate *Fructose 3-phosphate *Fructose 6-phosphate *Fructose 1,6-bisphosphate *Fructose 2,6-bisphosphate
Each fructose phosphate plays a specific role in metabolism. For example, fructose 2,6-bisphosphate is an important allosteric regulator for the correlated regulation of glycolysis and gluconeogenesis based on hormonal nutritional signals.<ref name=":0" /> However, if fructose 2,6-bisphosphate levels become unregulated and result in a decrease in its production, gluconeogenesis is favored over glycolysis, which contributes to hepatic glucose output in diabetes.<ref>{{Cite journal |last1=Wu |first1=Chaodong |last2=Okar |first2=David A. |last3=Newgard |first3=Christopher B. |last4=Lange |first4=Alex J. |date=2002-01-01 |title=Increasing fructose 2,6-bisphosphate overcomes hepatic insulin resistance of type 2 diabetes |journal=American Journal of Physiology. Endocrinology and Metabolism |volume=282 |issue=1 |pages=E38–45 |doi=10.1152/ajpendo.2002.282.1.E38 |issn=0193-1849 |pmid=11739081}}</ref>
== Applications == Because of fructose phosphates' critical role in metabolism, their relevance spans clinical, dietary, and therapeutic contexts, including:<ref name=":1" />
* Hereditary fructose intolerance (HFI) * Fructose 1,6-bisphosphate deficiency * Metabolic syndrome and obesity *Targeting the inhibition of ketohexokinase as potential therapeutic strategy for fructose-induced metabolic disease.<ref>{{Cite journal |last1=Herman |first1=Mark A. |last2=Birnbaum |first2=Morris J. |date=2021-12-07 |title=Molecular aspects of fructose metabolism and metabolic disease |journal=Cell Metabolism |language=English |volume=33 |issue=12 |pages=2329–2354 |doi=10.1016/j.cmet.2021.09.010 |issn=1550-4131 |pmid=34619074|pmc=8665132 }}</ref>
==Nutritional science and guidelines==
Dietary fructose should be consumed in moderate amounts from around 25-40 g/day.<ref>{{Cite journal |last1=Agarwal |first1=Vishal |last2=Das |first2=Sambit |last3=Kapoor |first3=Nitin |last4=Prusty |first4=Binod |last5=Das |first5=Bijay |date=2024-11-21 |title=Dietary Fructose: A Literature Review of Current Evidence and Implications on Metabolic Health |journal=Cureus |volume=16 |issue=11 |article-number=e74143 |language=en |doi=10.7759/cureus.74143 |doi-access=free |issn=2168-8184 |pmc=11663027 |pmid=39712814}}</ref> However, the value may be different according to an individual's body structure and composition. Excessive intake of fructose may result in negative health outcomes, but should not be taken to be the only factor for any metabolic disease.
==References== {{Reflist}}
==External links== * {{MeshName|Fructosephosphates}} * [https://pubchem.ncbi.nlm.nih.gov/compound/440641 Pubchem - fructose-6-phosphate]
Category:Organophosphates