The subcellular distribution of major particulate neuraminidase and gangliosides in the rabbit cortex was determined. The neuraminidase and gangliosides were found to be present in: (a) the nerve endings; (b) the light membranes of microsomal origin ; (c) the myelin-rich preparation obtained from the crude mitochondrial fraction. Their distribution patterns were very similar also from the quantitative point of view; in fact 40 % of the neuraminidase activity and 43.5 % of the gangliosides were recovered in the nerve endings; 50% of the enzyme and 45% of the gangliosides in the light microsomal membranes; 8 % of the neuraminidase and 11 % of the gangliosides in the myelin-rich preparation. Conversely, the preparations enriched in nuclei, mitochondria and lysosomes were practically devoid of both neuraminidase and gangliosides. The ganglioside patterns of the different subcellular fractions were similar, except for the myelin-rich subfraction which contained higher amounts of monosialoganglioside GM1. The microsomal light membranes had a slightly lower content of trisialoganglioside GTIb and tetrasialoganglioside GQ1 than the nerve endings. These results may be considered consistent with the hypothesis that neuraminidase and gangliosides are fundamental components of the neuronal plasma membrane, thus following the distribution of the different neuronal fragments after homogenization and fractionation.
|Number of pages||12|
|Journal||Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism|
|Publication status||Published - Jun 21 1973|
ASJC Scopus subject areas