New Aspects in the Determination of Endogenous Membrane-Bound Sialidase in the CNS, Using 4-MU-NeuAc as an (Exogenous) Artificial Substrate
Determination of endogenous membrane-bound sialidase by means of a fluorometric assay using 4-Methyl-Umbelliferyl-NeuAc (4-MU-NeuAc) as an artificial (exogenous) substrate is commonly used because of its easy applicability, though the opinions regarding the reliability of this assay are partly contrary (Scheel et al.; 1985; Eur. J. Biochem. 153: 29–35; Potier; 1981; Perspectives in inherited metabolic diseases 4: 233–247; Edi. Ermes Mailand). In order to clarify this, an effort has been made to find out the analytical “weak-points” of this test and to apply it to different biological systems (acclimation/acclimatization of dwarf- and golden hamsters; ontogeny of trout and a cichlid fish).