The epinephrine-mediated “amplification cascade” of Figure 24.14 has six steps, all of which are catalytic with one exception. This cascade leads to the activation of glycogen phosphorylase. This enzyme acts in turn on glycogen to yield glucose-1-phosphate (G-1-P).
(a) Which step is not catalytic?
(b) If each catalytic step had a turnover (molecules of substrate acted on per molecule of enzyme) of 10, how many molecules of G-1-P would result from one molecule of epinephrine?
(c) What is the biochemical advantage of such a cascade?