22.214.171.124 - Fructose-bisphosphatase
- Fructose 1,6-bisphosphatase.
- Hexose diphosphatase.
beta-D-fructose 1,6-bisphosphate + H2O = beta-D-fructose 6-phosphate + phosphate
There are no Cofactors for this Enzyme
Fructose 1,6-bisphosphatase (FBPase) hydrolyses fructose 1,6-bis-phosphate to fructose 6-phosphate and phosphate. The enzyme plays a crucial role in gluconeogenesis, the formation of glucose from non-carbohydrate carbon containing substrates. The enzyme is only capable of catalysing the forward reaction, while phosphofructokinase catalyses the reverse reaction. Regulation of the two enzyme is performed by metabolites such as fructose 2,6 bis-phosphate, ensuring that enhances reactivity of one enzyme is accompanied by suppressed reactivity of the other.
There are three divalent metal cations present within the catalytic site. Mg(2+) at site one is directly coordinated to the 1-(OH) of the 6 fructose phosphate product as a fifth coordinating ligand. The cation is thought to stabilise the negative charge of the hydroxide group before the transfer of a proton from Asp68, which relays a proton from the substrate neutralises the product. The second metal coordinates to a nucleophilic water molecule, also polarised through hydrogen bonds to Asp74 and Glu98, which abstracts a proton from a second coordinated water. The resulting hydroxide ion is the attacking nucleophile, displacing the 6 fructose phosphate in an SN2 mechanism. The resulting oxide is protonated as stated above.
|AA||Uniprot||Uniprot Resid||PDB||PDB Resid|
inferred reaction step, native state of enzyme regenerated, proton transfer, overall product formed
Organism KM Value [mM] Substrate Comment Synechocystis sp. 0.21 D-fructose 1,6-bisphosphate mutant R176A, pH 8.0, 28°C Euglena gracilis 0.49 D-fructose 1,6-bisphosphate isozyme EgFBPaseII, pH 8.0, temperature not specified in the publication Lactobacillus delbrueckii subsp. lactis 0.6 beta-D-glucose 1,6-bisphosphate mutant enzyme H20A, in 50 mM K+HEPES pH 7.0 at 25°C Sulfurisphaera tokodaii 7.2 D-fructose 1,6-bisphosphate pH 7.8, 48°C, mutant enzyme Y348F Bacillus methanolicus 8.8 D-fructose 1,6-bisphosphate pH 7.7, 50°
Organism Temperature Range Comment Clonorchis sinensis 15 - 45 more than 70% of maxiumum activity Pisum sativum 30 - 70 30°C: about 40% of maximal activity, 70°C: about 60% of maximal activity Thermococcus kodakarensis 37 - 95 the enzyme shows a nearly linear increase in activity between 37°C and 95°C
Organism pH Range Comment Pisum sativum 5.5 - 7.5 pH 5.5: about 20% of maximal activity, pH 7.5: about 25% of maximal activity Euglena gracilis 6 - 9 activity range, profile overview, recombinant enzyme Saccharomyces cerevisiae 6 - 11 pH 6.0: about 25% of maximal activity, pH 11.0.: 55% of maximal activity Pelophylax lessonae 6 - 9.5 activity range Bos taurus 6.3 - 10 pH 6.3: about 30% of maximal activity, pH 10.0: about 45% of maximal activity
- Phosphofructokinase-1 and fructose bisphosphatase-1 in canine liver and kidney.
- Metabolic regulation of calcium pumps in pancreatic cancer: role of phosphofructokinase-fructose-bisphosphatase-3 (PFKFB3).
- Fructose bisphosphatase 2 overexpression increases glucose uptake in skeletal muscle.
- Novel fructose bisphosphatase 1 gene mutation presenting as recurrent episodes of vomiting in an Indian child.
- Transforming growth factor β1 upregulates 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase-4 expression in A549 and MCF-10A cells.
- Come, Sweet Death: Why Endothelial Cells Die in Fructose.
- Viral infections inhibit saponin biosynthesis and photosynthesis in Panax notoginseng.
- A novel variant in the FBP1 gene causes fructose-1,6-bisphosphatase deficiency through increased ubiquitination.
- Role of PFKFB3-driven glycolysis in sepsis.
- Weak neuronal glycolysis sustains cognition and organismal fitness
- Beet leaf (beta vulgaris L.) extract attenuates iron-induced testicular toxicity: Experimental and computational approach.