Glycogens isolation

Orpin, C. G., Huskisson, N. S. Ward, P. F. V. (1976). Molecular structure and morphology of glycogen isolated from the cestode Moniezia expansa. Parasitology, 73 83-95. 

Parsons TF, Preiss J. Biosynthesis of bacterial glycogen. Isolation and characterization of the pyridoxal-P allosteric activator site and the ADP-glucose protected pyridoxal-P binding site of Escherichia coli B ADP-glucose synthase. J. Biol. Chem. 1978 253 7638-7645. 

Glycogen Isolation 1. [Courtesy of Dr. Peter J. Roach, Indiana University School of Medicine.]... 

A liver glycogen isolated from subjects having type IV glycogenosis... 

In the late 1940s Stacey, with the able and enthusiastic assistance of Paul Kent, examined polysaccharide material from Mycobacterium tuberculosis human strain. From heat-killed cells, two stable, serologically specific polysaccharide fractions and a degraded bacterial glycogen were isolated and examined. 

Eleven defects in the metabolism of glycogen have been reported nine of them affect skeletal muscle directly (see Figure 5), but only glycogenosis type II (acid maltase deficiency) and glycogenesis type V (myophosphorylase deficiency) are reasonably common the rest are rare and some have been recorded in isolated case studies only. 

It is not proposed to include the better known polysaccharides or the plant gums in the group because they can be conveniently classified separately. It must be pointed out, however, that some of these may occur naturally in firm combination with protein as instanced by the shock effect observed when solutions of crude inulin are injected into animals and by the reported isolation of desmoglycogen4 and glycogen combined with myosin.6... 

The isolation124,130 131 137 of, or failure to isolate,116 131 -139 D-glucose from oxidized, hydrolyzed starches and glycogens has been regarded as an indication of the presence or absence of (1 — 2) or (1 —> 3) branching. 

The astrocyte-neuron lactate shuttle hypothesis is controversial. In recent years the possibility that lactate, formed within the brain and released by astrocytes, is an important neuronal substrate both for energy and incorporation into neurotransmitters has been the subject of many studies and considerable controversy. There is evidence that suggests transient release of lactate in human brain on stimulation [48,8,88], Little is known about the highly active metabolism that takes place in the many elaborate, lamellar distal processes of astrocytes dispersed through the neuropil and interacting with an estimated >100,000 synapses [82, and references therein]. However, it is well established that astrocytes do respond to neuronal activity [89], For example, in the isolated mouse optic nerve preparation, upon stimulation, astrocytic glycogen... 

Glycogen phosphorylase isoenzymes have been isolated from liver, brain and skeletal muscle. All forms are subject to covalent control with conversion of the inactive forms (GP-b) to the active forms (GP-a) by phosphorylation on specific serine residues. This phosphorylation step, mediated by the enzyme phosphorylase kinase, is initiated by glucagon stimulation of the hepatocyte. Indeed, the same cAMP cascade which inhibits glycogen synthesis simultaneously stimulates glycogenolysis, giving us an excellent example of reciprocal control. 

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