Farmasevtika instituti farmakologiya va klinik farmatsiya kafedrasi

 
Glucose Glucose-6-phosphateglucokinase or hexokinase +ATP 
This phosphorylation is promoted mainly by the enzyme 
glucokinase 
in the liver and by 
hexokinase 
in most other cells. 
The phosphorylation of glucose is almost completely irreversible except in the liver cells, the renal 
tubular epithelial cells, and the intestinal epithelial cells; in these cells, another enzyme, 
glucose 
phosphatase
, is also available, and when this is activated, it can reverse the reaction. In most tissues of 
the body, phosphorylation serves to 
capture 
the glucose in the cell.That is, because of its almost 
instantaneous binding with phosphate, the glucose will not diffuse back out, except from those special 
cells, especially liver cells, that have phosphatase. 
Glycogen Is Stored in Liver and Muscle 
After absorption into a cell, glucose can be used immediately for release of energy to the cell, or it 
can be stored in the form of 
glycogen
, which is a large polymer of glucose.All cells of the body are 
capable of storing at least some glycogen, but certain cells can store large amounts, especially 
liver 
cells
, which can store up to 5 to 8 percent of their weight as glycogen, and 
muscle cells
, which can 
store up to 1 to 3 percent glycogen.
by the Glycolytic Pathway 
Because complete oxidation of 1 gram-mole of glucose releases 
686,000 calories of energy and only 12,000 calories of energy are required to form 1 gram-mole of 
ATP, energy would be wasted if glucose were decomposed all at once into water and carbon dioxide 
while forming only a single ATP molecule. Fortunately, cells of the body contain special 
proteinenzymes that cause the glucose molecule to split a little at a time in many successive steps, so 
that its energy is released in small packets to form one molecule of ATP at a time, forming a total of 38 
moles of ATP for each mole of glucose metabolized by the cells 

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