Which of the following enzyme activity decreases in fasting?
Phosphofructokinase 1 (PFK1) provides the first enzymatic step at which a glucose molecule becomes committed to glycolysis and therefore is subject to regulation (Nelson & Cox, 2008). PFK1 activity depends on the concentrations of AMP, ADP, and ATP with allosteric activation by AMP and ADP and allosteric inhibition by ATP. In the fasting state, glucagon causes the liver to mobilize glucose from glycogen (glycogenolysis) and to synthesize glucose from oxaloacetate and glycerol (gluconeogenesis). Glucagon stimulates an increase in cAMP, leading to an increase in phosphorylation by protein kinase A. The wave of phosphorylation that spreads through the liver cell activates enzymes such as glycogen phosphorylase that are involved in glycogen degradation while simultaneously inhibiting glycogen synthesis. Inhibition of glycogen synthase prevents futile resynthesis of glycogen from glucose 1-phosphate (G1P) UDP-Glc. Glucose-6-phosphatase (G6Pase), a gluconeogenic enzyme that is present in the liver but not in muscle, then conves G6P to glucose for release into the blood. REF: Lippincott book of biochemistry 6th ed.
Hormone sensitive lipase
Glycogen phosphorylase
Acetyl CoA Carboxylase
Phosphofructokinase I
All India exam