Figure 12.16Activation of glycogen phosphorylase and
inactivation of glycogen synthase. Phosphorylation reactions
catalyzed by protein kinase A increase glycogen degradation. A
green background indicates activated enzymes; a red background
indicates inactivated enzymes. Green arrows signify activation; red
arrows signify inactivation.Figure 12.17Activation of glycogen
synthase and inactivation of glycogen phosphorylase. Hydrolysis of
phosphate monoester bonds catalyzed by protein phosphatase-1
increases glycogen synthesis.Figure 12.18Regulation of glycogen
metabolism by glucose in the liver. Inhibition of protein
phosphatase-1 by glycogen phosphorylase a is relieved when glucose
binds to the phosphorylase. Glycogen phosphorylase is then
inactivated, and glycogen synthase is activated.Figure
16.24Triacylglycerol degradation in adipocytes. Epinephrine
initiates the activation of protein kinase A, which catalyzes the
phosphorylation and activation of hormone-sensitive lipase. The
lipase catalyzes the hydrolysis of triacylglycerols to
monoacylglycerols and free fatty acids. The hydrolysis of
monoacylglycerols is catalyzed by monoacylglycerol lipase.
