Biochemistry 2280A Lecture Notes - Citric Acid, Skeletal Muscle, Hydrolysis

• School: Western University
• Department: Biochemistry
• Course: Biochemistry 2280A
• Professor: Prof

Document Summary

Carbohydrate metabolism encompasses 4 key bodily actions: glycogen synthesis and breakdown, glycolysis and fermentation, gluconeogenesis, and the pentose phosphate pathway. As coupled utp hydrolysis is required to convert glucose-1-phosphate into glycogen, it is unlikely that glycogen synthase will convert glycogen into glucose-1-phosphate. An equilibrium between glucose-6-phosphate and glucose-1-phosphate is also established (they are energetically neutral to each other). There is no equilibrium between glycogen and glucose-1-phosphate because two different enzymes are utilized in catalysis. In skeletal muscle cells, glucose-6-phosphate allosterically activates glycogen synthase, while amp activates glycogen phosphorylase. Atp and glucose-6-phosphate are both inhibitors of glycogen phosphorylase. The liver has isozymes, enabling it to respond to regulation in a slightly different manner than the muscles do (neither atp nor amp regulate/inhibit glycogen phosphorylase activity in the liver). Glucose is an allosteric inhibitor of glycogen phosphorylase (high blood sugar), while glucose-6-phosphate allosterically activates glycogen synthase (same as in the muscles).