Glukos6fosfat

Glukos6fosfat, often abbreviated as G6P, is a crucial intermediate molecule in cellular metabolism. It is formed when glucose is phosphorylated by the enzyme hexokinase in most cells or glucokinase in the liver and pancreas, adding a phosphate group to the sixth carbon atom of glucose. This phosphorylation step is essentially irreversible and serves to trap glucose within the cell, preventing its diffusion out.

G6P plays a central role in several metabolic pathways. Its primary function is in glycolysis, the breakdown of glucose to produce ATP, the cell's main energy currency. G6P is the first committed step in this pathway. Beyond glycolysis, G6P is also a precursor for glycogen synthesis, where glucose units are stored for later use, and for the pentose phosphate pathway, which generates NADPH for biosynthesis and antioxidant defense, as well as precursor molecules for nucleotide synthesis. In the liver and kidneys, G6P can also be dephosphorylated by glucose-6-phosphatase to release free glucose into the bloodstream, a critical step in maintaining blood glucose homeostasis. Defects in the enzymes involved in G6P metabolism can lead to various metabolic disorders.