acid-phosphatase and Mucopolysaccharidosis-III

Acid phosphatases in brain and cultured lymphoblasts from patients affected with neuronal ceroid-lipofuscinoses (NCL) were studied by starch gel electrophoresis. After electrophoresis the gel was incubated with 4-methyl umbelliferyl phosphate at pH 4.5 and the fluorescent reaction product was visualized under ultraviolet light. Control brain showed a single band with mobility of about 1 cm while NCL patients showed two additional fast moving bands. In the late-infantile, and in the adult form (Kufs disease), the middle band was prominent while the fast moving band was predominant in juvenile NCL. In long-term lymphoblasts, controls showed a single band of acid phosphatase activity while both juvenile and late-infantile NCL showed two additional fast moving bands. Obligate heterozygotes showed reduced levels of the fast moving bands. Fluorometric assay of acid phosphatase using 4-methylumbelliferyl phosphate as substrate showed a 2-fold increase in activity in the patients. The increased acid phosphatase activity is completely inhibited by tartrate. Lymphocyte hexosamnidase activities were unchanged in NCL patients lymphoblasts. Studies on brains of NCL patients and on cultured lymphoblasts from families with late-infantile and juvenile form of NCL showed that abnormal acid phosphatase is characteristic of NCL.

Topics: Acid Phosphatase; Adolescent; Adult; beta-N-Acetylhexosaminidases; Brain; Cell Line; Cells, Cultured; Child, Preschool; Family; Gaucher Disease; Humans; Infant; Lymphocytes; Mucopolysaccharidosis III; Neuronal Ceroid-Lipofuscinoses; Substrate Specificity

Acetyl-CoA:alpha-glucosaminide N-acetyltransferase is a lysosomal-membrane enzyme deficient in a genetic disorder, Sanfilippo disease type C. The enzyme catalyzes the transfer of an acetyl group from cytoplasmic acetyl-coenzyme A (acetyl-CoA) to terminal alpha-glucosamine residues of heparan sulfate within the organelle. Previous kinetic experiments indicated that the enzyme carries out a transmembrane acetylation via a ping-pong mechanism; the reaction can therefore be dissected into two half reactions--acetylation of the enzyme, and transfer of the acetyl group to glucosamine. Cells derived from patients were found to differ in their ability to perform each half reaction. Five cell lines (derived from three families) were able to catalyze acetylation of the lysosomal membrane and to carry out acetyl-CoA/CoA exchange, whereas a sixth cell line was devoid of this activity.

Topics: Acetylation; Acetyltransferases; Acid Phosphatase; beta-Glucosidase; Biological Transport; Coenzyme A; Glucosamine; Heparitin Sulfate; Hexosaminidases; Humans; Intracellular Membranes; Lysosomes; Membrane Proteins; Mucopolysaccharidoses; Mucopolysaccharidosis III

An autopsy case of a 9 years and 5 months old gargoyle girl diagnosed as Sanfilippo B syndrome by the biochemical demonstration of a large amount of heparan sulfate in urine and some organs and of deficiency of alpha-N-acetyl-D-glucosaminidase in the liver and brain was reported. The morphological changes characterized by cytoplasmic swelling and vacuolization were more generalized than those which had been described in previously reported cases. Histochemically, accumulation of variable amounts of acidic glycosaminoglycans and compound lipids, presumably gangliosides and phospholipids, was substantiated in the vacuolated cells of various visceral organs and in the ballooned neuronal cells. Ultrastructurally, numerous inclusions found in these cells were largely divided into two types; flocculent reticulogranular and osmiophilic, mostly laminated materials, many of which were bound by a single unit membrane. Enzyme cytochemistry proved acid phosphatase activity in the majority of the inclusions in fibroblasts and fibrocytes biopsied from the skin. Rough endoplasmic reticulum in these cells was markedly dilated with reticulogranular materials. The morphological changes of the present case and their pathogenesis were discussed.

Topics: Acetylglucosaminidase; Acid Phosphatase; Brain; Child; Female; Galactosidases; Glucosidases; Glycosaminoglycans; Heparitin Sulfate; Humans; Lipid Metabolism; Liver; Mucopolysaccharidoses; Mucopolysaccharidosis III; Organ Specificity