PFKL

PFKL is the gene that encodes the liver-type subunit of phosphofructokinase-1 (PFK-1), a key enzyme in glycolysis. PFK-1 catalyzes the ATP-dependent phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate, a rate-limiting step that commits glucose to energy production and biosynthetic pathways.

In humans, PFK-1 is a tetramer composed of subunits encoded by PFKM (muscle), PFKL (liver), and PFKP (platelet). PFKL encodes the liver-type catalytic subunit. The enzyme can assemble as homo- or heterotetramers, and tissue-specific expression of these subunits influences the regulatory properties and kinetic behavior of the complex.

PFK-1 is allosterically regulated. ATP generally inhibits PFK-1, while ADP and AMP relieve inhibition; citrate also inhibits, and fructose-2,6-bisphosphate is a potent activator. The sensitivity to these regulators can vary with subunit composition, so PFKL-containing tetramers may respond differently to cellular signals than other isoforms.

Physiological and clinical relevance: PFKL participates in glycolytic flux in liver and other tissues, contributing to cellular energy production and metabolic balance. Changes in PFKL expression or activity can impact glucose metabolism. In research contexts, alterations in PFKL have been studied for their potential roles in cancer metabolism and metabolic disorders, reflecting the enzyme’s central role in regulating glycolysis and energy homeostasis.