Figure 18-1a Structure of glycogen. (a) Molecular formula. (b) Schematic diagram illustrating its branched structure.

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Figure 18-2c X-Ray structure of rabbit muscle glycogen phosphorylase. (c) An interpretive “low-

resolution” drawing of Part b showing the enzyme’s various ligand-binding sites.

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Pyridoxal Phosphate

Figure 18-3The reaction mechanism of glycogen phosphorylase.

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Figure 18-4 The mechanism of action of

phosphoglucomutase.

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Figure 18-5 Reactions catalyzed by debranching enzyme.

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Figure 18-6 Reaction catalyzed by UDP–glucose pyrophos-phorylase.

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Figure 18-7 Reaction catalyzed by glycogen

synthase.

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Figure 18-8 The branching of glycogen.

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Figure 18-9 The control of glycogen phosphorylase activity.

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Figure 18-10aConformational changes in glycogen phosphorylase. (a) Ribbon diagram of one subunit (T-state) in absence of allosteric effectors.

a.

(b) Ribbon diagram of one subunit (R-state) with bound AMP. b.

Figure 18-10b

Conformational changes in

glycogen phosphorylase

. (b) The portion of the

glycogen phosphorylase a dimer in the vicinity of the

dimer interface.

Figure 18-11a A monocyclic enzyme cascade. (a) General scheme, where F and R are, respectively, the

modifying and demodifying enzymes.

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Figure 18-11b A monocyclic enzyme cascade.(b) Chemical equations for the interconversion of the

target enzyme’s unmodified and modified forms Eb and Ea.

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Figure 18-12 A bicyclic enzyme cascade.

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Figure 18-13 Schematic diagram of the major enzymatic modification/demodification systems involved

in the control of glycogen metabolism in muscle.

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Figure 18-14 X-ray structure of the catalytic (C) subunit of mouse protein kinase A (PKA).

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Figure 18-15 X-ray structure of the regulatory (R) subunit of

bovine protein kinase A (PKA).

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Figure 18-16 X-Ray structure of rat testis calmodulin.

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Figure 18-17 EF hand. P

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Figure 18-18a. NMR structure of (Ca2+)4–CaM from Drosophila melanogaster in complex with its 26-residue target polypeptide

from rabbit skeletal muscle myosin light chain kinase (MLCK). (a) A view of the complex in which the N-terminus of the target

polypeptide is on the right.

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Figure 18-18b. NMR structure of (Ca2+)4–CaM from Drosophila melanogaster in complex with its 26-residue target polypeptide

from rabbit skeletal muscle myosin light chain kinase (MLCK). (b) The perpendicular view as seen from the right side of Part a.

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Figure 18-19Schematic diagram of the Ca2+–CaM-

dependent activation of protein kinases.

Figure 18-21 The antagonistic effects of insulin and epinephrine on glycogen metabolism in muscle.

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Figure 18-22 The enzymatic activities of phosphorylase a and glycogen synthase in

mouse liver in response to an infusion of glucose.

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Figure 18-23 Comparison of the relative enzymatic activities of hexokinase and glucokinase over the

physiological blood glucose range.

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Figure 18-24 Formation and degradation of -D-fructose-2,6-bisphosphate as catalyzed by PFK-2 and

FBPase-2.

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Figure 18-25 X-ray structure of the H256A mutant of rat testis

PFK-2/FBPase-2.

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Figure 18-26aThe liver’s response to stress. (a) Stimulation of α-adrenoreceptors by epinephrine activates phospholipase C to hydrolyze PIP2 to IP3 and DAG.

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Figure 18-26bThe liver’s response to stress. (b) The participation of two second messenger systems.

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Figure 18-27 The ADP concentration in human forearm muscles during rest and following exertion in normal individuals and those with McArdle’s disease.

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(Muscle Phosphorylase Deficiency)

Table 18-1Hereditary Glycogen Storage Diseases.

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“Alfonse, Biochemistry makes my head hurt!!”\