acid-phosphatase and Glycogen-Storage-Disease-Type-I

We show here that the amino acid residues contributing to the active sites of the vanadate containing haloperoxidases are conserved within three families of acid phosphatases; this suggests that the active sites of these enzymes are very similar. This is confirmed by activity measurements showing that apochloroperoxidase exhibits phosphatase activity. These observations not only reveal interesting evolutionary relationships between these groups of enzymes but may also have important implications for the research on acid phosphatases, especially glucose-6-phosphatase-the enzyme affected in von Gierke disease-of which the predicted membrane topology may have to be reconsidered.

Topics: Acid Phosphatase; Amino Acid Sequence; Animals; Binding Sites; Glucose-6-Phosphatase; Glycogen Storage Disease Type I; Humans; Kinetics; Molecular Sequence Data; Peroxidases; Phosphoric Monoester Hydrolases

Feeding of fructose for 7 days has been morphometrically shown to induce a SER-reduction and an accumulation of glycogen in rat liver cells. This hypothetical model "glycogenosis" is investigated with histochemical methods.. Rats are given a solution of 60% fructose in water as only nutritional source. Controls are given a solution of 60% glucose in water, an isocaloric Altromin-R-standard diet and an Altromin-R-standard diet ad libitum. Reversion of fructose induced metabolic changes is investigated by a 7 days fructose diet followed by an 1-4 days Altromin-R-standard diet ad libitum. Glycogen and glycogen metabolizing enzymes are demonstrated after a 7 days diet and in the course of an 1-7 days fructose diet.. Feeding of fructose leads to a high glycogen content, combined with a high activity of glycogen-phosphorylase and glucose-6-phosphatase in the liver parenchyma. Glycogen-synthetase activity increases during the first 4 days and then it drops to a low level. A pathological alteration of liver cell metabolism seems to be improbable, for all fructose induced changes are reversibel after 2 days of Altromin-R-standard diet. Glucose-6-phosphatase, as a marker-enzyme of the smooth endoplasmatic reticulum, is discussed to become activated by disruption of SER membranes due to fructose.

Topics: Acid Phosphatase; Animals; Disease Models, Animal; Endoplasmic Reticulum; Fructose; Glucose; Glucose-6-Phosphatase; Glycogen Storage Disease; Glycogen Storage Disease Type I; Glycogen Synthase; Histocytochemistry; Liver; Liver Glycogen; Male; Phosphorylases; Rats

Topics: Acid Phosphatase; Alkaline Phosphatase; Diagnosis, Differential; Glucosidases; Glycogen Storage Disease; Glycogen Storage Disease Type I; Humans; Liver; Liver Cirrhosis; Liver Glycogen; Phosphorylase Kinase