Phosphofructokinaseについて
| Phosphofructokinase | |||
|---|---|---|---|
 | |||
| Identifiers | |||
| Symbol | Ppfruckinase | ||
| Pfam | PF00365 | ||
| InterPro | IPR000023 | ||
| PROSITE | PDOC00336 | ||
| |||
Phosphofructokinase (PFK) is a kinase enzyme that phosphorylates fructose 6-phosphate in glycolysis.
The enzyme-catalysed transfer of a phosphoryl group from ATP is an important reaction in a wide variety of biological processes.
Phosphofructokinase catalyses the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate, a key regulatory step in the glycolytic pathway.[2]
It is allosterically inhibited by ATP and allosterically activated by AMP, thus indicating the cell's energetic needs when it undergoes the glycolytic pathway.
PFK exists as a homotetramer in bacteria and mammals (where each monomer possesses 2 similar domains) and as an octomer in yeast (where there are 4 alpha- (PFK1) and 4 beta-chains (PFK2), the latter, like the mammalian monomers, possessing 2 similar domains[3]).
This protein may use the morpheein model of allosteric regulation.[5]
PFK is about 300 amino acids in length, and structural studies of the bacterial enzyme have shown it comprises two similar (alpha/beta) lobes: one involved in ATP binding and the other housing both the substrate-binding site and the allosteric site (a regulatory binding site distinct from the active site, but that affects enzyme activity).
The identical tetramer subunits adopt 2 different conformations: in a 'closed' state, the bound magnesium ion bridges the phosphoryl groups of the enzyme products (ADP and fructose-1,6-bisphosphate); and in an 'open' state, the magnesium ion binds only the ADP,[6] as the 2 products are now further apart. These conformations are thought to be successive stages of a reaction pathway that requires subunit closure to bring the 2 molecules sufficiently close to react.[6]
The reverse reaction is catalyzed by the enzyme Fructose-1,6-bisphosphatase
2024年7月9日 | カテゴリー：糖尿病 |
