|Other names:||6-Phosphofructokinase, 6-Phosphofructo-1-kinase, Fructose-6-P 1-Kinase, Fructose-6-phosphate 1-Phosphotransferase|
|Gene type:||protein coding|
|Molecular Weight:||82,000 (Da)|
|Protein type:||Enzyme: Kinase|
|Functions:||converts fructose 6-phosphate + ATP to fructose 1,6-bisphosphate + ADP|
|Pathway(s):||Citric acid cycle, Glycolysis|
Phosphofructokinase-1 (PFK-1) is the most important regulatory enzyme (EC 184.108.40.206) of glycolysis. It is an allosteric enzyme made of 4 subunits and controlled by several activators and inhibitors. PFK-1 catalyzes one of the important "committed" steps of glycolysis, the conversion of fructose 6-phosphate and ATP to fructose 1,6-bisphosphate and ADP.
|α-D-fructose 6-phosphate||Phosphofructokinase-1||α-D-fructose 1,6-bisphosphate|
This step is subject to extensive regulation since it is not only irreversible, but also because the original substrate is forced to proceed down the glycolytic pathway after this step. This leads to a precise control of glucose and the other monosaccharides galactose and fructose going down the glycolysis pathway. Before this enzyme's reaction, glucose-6-phosphate can potentially travel down the pentose phosphate pathway, or be converted to glucose-1-phosphate and polymerized into the storage form Glycogen.
PFK1 is allosterically inhibited by ATP and citrate (from the citric acid cycle) and its product. It is also inhibited by low pH to prevent the accumulation of hydrogen ions in muscle. The enzyme has two sites with different affinities for ATP which is both a substrate and an inhibitor.
PFK is inhibited by glucagon through repression of synthesis.
There are three phosphofructokinase genes in humans:
- PFK2 (converts fructose 6-phosphate to fructose 2,6-bisphosphate through on site, or the opposite, on another site)
- PFP (reversibly interconverts fructose 6-phosphate and fructose 1,6-bisphosphate using inorganic pyrophosphate (rather than ATP)
- fructose bisphosphatase (hydrolyses fructose 1,6-bisphosphate to fructose 6-phosphate)
Phosphotransferases/kinases (EC 2.7)
|2.7.1 - OH acceptor||Hexo- - Gluco- - Fructo- (Hepatic fructo-) - Galacto- - Phosphofructo- (1, 2) - Thymidine - NAD+ - Glycerol - Pantothenate - Mevalonate - Pyruvate - Deoxycytidine - PFP - Diacylglycerol - Bruton's tyrosine - Phosphoinositide 3 (Class I PI 3, Class II PI 3) - Sphingosine|
|2.7.2 - COOH acceptor||Phosphoglycerate - Aspartate|
|2.7.3 - N acceptor||Creatine|
|2.7.4 - PO4 acceptor||Phosphomevalonate - Adenylate - Nucleoside-diphosphate|
|2.7.6 - P2O7||Ribose-phosphate diphosphokinase - Thiamine pyrophosphokinase|
|2.7.7 - nucleotidyl-||Integrase - PNPase - Polymerase - RNase PH - UDP-glucose pyrophosphorylase - Galactose-1-phosphate uridylyltransferase -Terminal deoxynucleotidyl transferase - RNA replicase - Reverse transcriptase (Telomerase) - Transposase|
|2.7.8 - other phos.||N-acetylglucosamine-1-phosphate transferase|
|2.7.10-11 - protein||Tyrosine - Serine/threonine-specific|
Carbohydrate metabolism: glycolysis/gluconeogenesis enzymes
|Glycolysis||Glucokinase/Hexokinase/Glucose 6-phosphatase - Glucose isomerase - Phosphofructokinase 1/Fructose 1,6-bisphosphatase - Aldolase - Triosephosphate isomerase - Glyceraldehyde 3-phosphate dehydrogenase - Phosphoglycerate kinase - Phosphoglycerate mutase - Enolase - Pyruvate kinase|
|Gluconeogenesis only||Pyruvate carboxylase - Phosphoenolpyruvate carboxykinase - from lactate (Cori cycle): Lactate dehydrogenase - from alanine (Alanine cycle): Alanine transaminase|
|Regulatory||Phosphofructokinase 2/Fructose 2,6-bisphosphatase - Bisphosphoglycerate mutase|
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