Cell disease: desialylation of beta-hexosaminidase and its effect on uptake by fibroblasts.
The pinocytosis by fibroblasts of beta-hexosaminidase (EC 3.2.1.30) excreted by cultured skin fibroblasts from a patient with I-cell disease was not enhanced by neuraminidase treatment of the enzyme. The uptake of sialic acid-rich normal plasma beta-hexosaminidase was minimal and neuraminidase treatment did not appreciably enhance uptake. In contrast, sialic acid-rich normal seminal fluid beta-hexosaminidase was readily pinocytosed regardless of neuraminidase treatment. Thus the presence of sialic acid on beta-hexosaminidase does not influence uptake and a neuraminidase deficiency in I-cell disease may not be directly responsible for excessive extracellular enzyme.
D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism; D006596:Hexosaminidases / Q000378:metabolism*; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D009081:Mucolipidoses / Q000503:physiopathology*; D009439:Neuraminidase / Q000172:deficiency; D010873:Pinocytosis; D012794:Sialic Acids / Q000378:metabolism*; D012867:Skin / Q000378:metabolism
D012794:Sialic Acids; D006596:Hexosaminidases; D009439:Neuraminidase