Fosfoheksoze

Fosfoheksoze are a group of phosphorylated six-carbon sugars. The most common and biologically significant fosfoheksoze are glucose-6-phosphate and fructose-6-phosphate. These molecules play crucial roles in carbohydrate metabolism, serving as intermediates in glycolysis, gluconeogenesis, and the pentose phosphate pathway.

Glucose-6-phosphate is formed when glucose is phosphorylated by the enzyme hexokinase or glucokinase. This phosphorylation traps glucose within the cell and is the first committed step in glycolysis. It is also a precursor for glycogen synthesis and the pentose phosphate pathway, which generates NADPH and pentose sugars.

Fructose-6-phosphate is an isomer of glucose-6-phosphate and is formed by the enzyme phosphoglucose isomerase. It is a key intermediate in glycolysis, being further phosphorylated to fructose-1,6-bisphosphate. It also participates in the synthesis of other carbohydrates.

The interconversion of glucose-6-phosphate and fructose-6-phosphate, along with their other phosphorylated derivatives, are tightly regulated processes essential for maintaining cellular energy homeostasis and providing building blocks for biosynthesis. The state of fosfoheksoze within a cell is a sensitive indicator of metabolic activity and cellular needs.