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Fig. 1 | Orphanet Journal of Rare Diseases

Fig. 1

From: Hepatic glycogen storage diseases type 0, VI and IX: description of an italian cohort

Fig. 1

Main cytoplasmatic pathways involved in glycogen synthesis and breakdown in the liver cell. A, Glucokinase: phosphorylates glucose to glucose 6-phosphate; B, Phosphoglucomutase: shifts phosphate to create glucose 1-phosphate; C, UDP-glucose pyrophosphorylase: combines glucose 6-phosphate with UTP to uridine diphosphate; D, UDP-glucose:glycogenin glucosyltransferase: glycogenin catalyses its own glycosylation until a base of 5–13 glucose molecules; E, Glycogen synthase: incorporates glucose into glycogen via an α-1,4-glycosidic bond; F, Branching enzyme: every 10 to 14 glucose units, catalyses the shift of seven glucose molecules to a side branch (light blue), connected with an α-1,6-glycosidic bond; G, Glycogen phosphorylase: breaks peripheral α-1,4-glycosidic bond to release glucose 1-phosphate (purple); H, Glycogen phosphorylase kinase: phosphorylates glycogen phosphorylase triggering a conformational shift to a more active form; I, Debranching enzyme: when four molecules remain on a side chain, it transfers three of those to a primary chain (red); J, α-1,6-glucosidase: removes the last glucose from a side chain; K, Phosphoglucomutase: converts glucose 6-phosphate to glucose 1-phosphate; L, Glucose 6-phosphatase: removes phosphate group from glucose 6-phosphate

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