2. ๏ Phosphorylated intermediates are ionized at pH 7,
giving each glycolytic intermediate a net negative
charge.
๏ Charged intermediates cannot pass through the
hydrophobic lipid membrane that's why the plasma
membrane is impermeable to charged molecules.
๏ Therefore, phosphorylated intermediates cannot
diffuse out of the cell.
3. ๏ Phosphorylated substrates have more affinity for
enzymes than un phosphorylated substrates.
๏ Phosphoryl groups are essential components in the
enzymatic conservation of metabolic energy.
๏ High-energy phosphate compounds formed in
glycolysis (1,3-bisphosphoglycerate and
phosphoenolpyruvate) donate phosphoryl groups to
ADP to form ATP.
4. ๏ Mg-ATP is the main substrate for kinases. Binding of
phosphate groups to the active sites of enzymes lowers
the activation energy and increases the specificity of
the enzymatic reactions.
๏ The phosphate groups of ADP, ATP, and the glycolytic
intermediates easily form complexes with Mg2+.
๏ In metabolic reactions, phosphorylated intermediates
play an important role in energy conservation.
5. โข Cells maintain concentration gradient of glucose in
cytoplasm by phosphorylating glucose to glucose-6-
phosphate and it allows more glucose to enter the cell
from the blood.
โข Phosphorylation and dephosphorylation also regulate
the forward and backward reactions in those reactions
that are not at equilibrium.
