Quantitative Aspects of Pinocytosis and the Intracellular Fate of N-acetyl-α-D-glucosaminidase in Sanfilippo B Fibroblasts

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Abstract

The cellular uptake of N-acetyl-α-D-glucosaminidase, the deficient enzyme in Sanfilippo B disease, and the intracellular fate and metabolic effect of this enzyme have been investigated in Sanfilippo B and normal fibroblasts. For both genotypes the uptake is highly efficient (up to 0.025 mU/h/mg cell protein), specific and constant over a period of at least 6 days. It is probable that the enzyme protein is taken up by adsorptive pinocytosis. The enzymatic activity as well as the biological activity towards 35SO4-labeled mucopolysaccharides persist in Sanfilippo B cells with a half-life of 34 h, indicating the intralysosomal localization of the pinocytosed enzyme.

Authors

K. von Figura, H. Kresse