phosphofructokinase

Fructose bisphosphatase does the opposite job as phosphofructokinase, and both these enzymes work only in one direction.

Ordinarily F-2,6-BP binds to and increases the activity of phosphofructokinase 1.

There are three phosphofructokinase genes in humans:

Humans genes encoding proteins possessing phosphofructokinase 2 activity include:

It belongs to the phosphofructokinase B (PfkB) family of sugar kinases.

The compound also inhibits the phosphofructokinase enzyme, leading to glycogen depletion and hepatic shift.

If the intracellular pH changes to 5 or lower, the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95%.

Fru-2,6-P strongly activates glucose breakdown in glycolysis through allosteric modulation of phosphofructokinase 1.

A diagnosis can be made through a muscle biopsy that shows excess glycogen and then further tests that will show the levels of phosphofructokinase enzyme.

Fructose bisphosphatase catalyses the reverse of the reaction which is catalysed by phosphofructokinase in glycolysis.

Some other examples of enzymes are phosphofructokinase and hexokinase, both of which are important for cellular respiration (glycolysis).

An additional ATP is used to phosphorylate fructose 6-phosphate into fructose 1,6-disphosphate by the help of phosphofructokinase.

This enzyme is also called ADP-6-phosphofructokinase, ADP-dependent phosphofructokinase.

Full tetrameric phosphofructokinase enzyme expressed in platelets can be composed of subunits P4, P3L, and P2L2.

When blood glucose levels are low, the secretion of glucagon leads to the phosphorylation of phosphofructokinase 2 which inhibits formation of fructose 2,6-bisphosphate.

This, in turn, increases the concentration of citrate in the cell, a very potent inhibitor of phosphofructokinase, the first rate-limiting step of glycolysis.

High concentrations of cytosolic citrate can inhibit phosphofructokinase, catalyst of one of the rate-limiting steps of glycolysis.

When TIGAR decreases F-2,6-BP levels, phosphofructokinase becomes less active whilst fructose-1,6-bisphosphatase activity increases.

Citrate is used for feedback inhibition, as it inhibits phosphofructokinase, an enzyme involved in glycolysis that catalyses formation of fructose 1,6-bisphosphate,a precursor of pyruvate.

Another instance in which negative allosteric modulation can be seen is between ATP and the enzyme Phosphofructokinase within the negative feedback loop that regulates glycolysis.

When ATP levels are high, ATP will bind to an allosteric site on phosphofructokinase, causing a change in the enzyme's three-dimensional shape.

The mutation impairs the ability of phosphofructokinase to phosphorylate fructose-6-phosphate prior to its cleavage into glyceraldehyde-3-phosphate which enters the energy generation phase of glycolysis, effectively limiting energy production.

Tarui's disease - An inborn error of glycogen metabolism characterized by phosphofructokinase deficiency in the muscles, associated with abnormal deposition of glycogen in muscle tissues.

One enzyme that utilises this reaction is phosphofructokinase (PFK), which catalyses the phosphorylation of fructose-6-phosphate to fructose-1,6- bisphosphate, a key regulatory step in the glycolytic pathway.

An example of an enzyme activator working in this way is fructose 2,6-bisphosphate, which activates phosphofructokinase 1 and increases the rate of glycolysis in response to the hormone insulin.