Fatty acid metabolism months, and, during this entire period, the energy is derived from degradation of fat stores. Migrating birds similarly build up large fat reserves before embarking on their intercontinental journeys. Thus the young adult human’s fat stores average between about 10–20 kg, but varies greatly depending on age, gender, and individual disposition. By contrast the human body stores only about 400 g of glycogen, of which 300 g is locked inside the skeletal muscles and is unavailable to the body as a whole. The 100 g or so of glycogen stored in the liver is depleted within one day of starvation.
Glycogen phosphorylase through greater organization and intersubunit interactions. This rotation of the tower helices leads to a rotation of the two subunits by 10˚ relative to one another, and more importantly disorders residues 282-286 (the 280s loop) that block access to the catalytic site in the T state but do not in the R state. The final, perhaps most curious site on the glycogen phosphorylase protein is the so-called glycogen storage site. Residues 397-437 form this structure, which allows the protein to covalently bind to the glycogen chain a full 30 Å from the catalytic site . This site is most likely