Glycogen storage

FIGURE 15.15 (a) The structure of a glycogen phosphorylase monomer, showing the locations of the catalytic site, the PLP cofactor site, the allosteric effector site, the glycogen storage site, the tower helix (residnes 262 throngh 278), and the snbnnit interface. 

A Chemical Investigation of Two Cases of Glycogen Storage Disease, S. A. Barker, M. Stacey, and M. A. L. Al-Farisi, Clin. Chim. Acta, 8 (1963) 311-314. 

Metabolic Myopathies Glycogen Storage Disease Disorders of Lipid Metabolism Respiratory Chain Disorders Mitochondrial DNA Abnormalities Myotonias, Periodic Paralyses, and Malignant Hyperpyrexia Myotonias... 

Figure 6. Glycogen storage in acid maltase (AM) deficiency in this late-onset case not all muscle fibers are affected.

In childhood and adult-onset forms of AM, more moderate glycogen storage and vacuolation of muscle are seen and not all fibers are affected. Although cardiomegaly is not apparent in childhood AMD, glycogen storage is detectable histologically in heart muscle. 

Glycogen storage disease is a generic term to describe a group of inherited disorders characterized by deposition of an abnormal type or quantity of glycogen in the tissues. The principal glycogenoses are summarized in Table 18—2. Deficiencies of adenylyl kinase and cAMP-dependent protein kinase have also been re-... 

Inherited deficiencies in specific enzymes of glycogen metabolism in both liver and muscle are the causes of glycogen storage diseases. 

There are important methodologic considerations which apply to the use of cultured amniotic fluid cells for the detection of biochemical disorders. The first is that the enzymes which can be sampled are those which are usually present in fibroblasts or fibroblast-like cells. Therefore, conditions such as phenylketonuria and glycogen storage disease type I, which are associated with deficiencies of enzymes present only in liver and kidney, are not amenable to this approach. The same also pertains to enzyme deficiencies affecting other specific tissues. 

Martiniuk, F., Chen, A., Donnabella, V. et al. (2000) Correction of glycogen storage disease type II by enzyme replacement with a recombinant human acid maltase produced by over-expression in a CHO-DHFR(neg) cell line. Biochemical and Biophysical Research Communications, 276 (3), 917-923. 

Muscle biopsy shows severe vacuolar myopathy with glycogen storage. On electron microscopy, the vacuoles correspond to pools of glycogen free in the cytoplasm. 

Soft parts of adults exposed for 28 days contained 188.0 mg Ag/kg DW vs. 3.0 mg/kg DW in controls No histopathology. During exposure, but not depuration, glycogen storage capacity was diminished. During depuration, silver concentrations decreased from 31.3 mg/kg DW soft parts to 12.8 vs. <10.0 in controls. Most of the insoluble accumulated silver was sequestered as Ag2S in amoebocytes and basement membranes... 

In the well-fed state, galactose can enter glycolysis or contribute to glycogen storage... 

Important genetic deficiencies, listed in Table 1-14-3, are classed as glycogen storage diseases because all are characterized by accumulation of glycogen in one or more tissues. 

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