Disease relevance of Neu3

• Competitive inhibition kinetics were observed when 1,2, and 3 were tested with the lysosomal sialidase (cultured fibroblasts) and the plasma membrane sialidase (adenovirus DNA-transformed, human embryonic kidney cells), giving a Ki of about 10 microM for both enzymes with all three compounds [1].
• Approximately the same amount of sialic acid is releasable from membrane sialolipid by the action of exogenous Vibrio sialidase; almost twice as much is releasable from sialoglycoprotein by this enzyme as compared with the intrinsic membrane sialidase [2].
• Differential functional relevance of a plasma membrane ganglioside sialidase in cholinergic and adrenergic neuroblastoma cell lines [3].

High impact information on Neu3

• The remainder of the membrane sialidase-susceptible sialic acid was released in a second, slower stage [2].
• The results of this study indicate that both glycolipid- and glycoprotein-bound sialic acid in the synaptic membrane are releasable in situ by the action of the intrinsic synaptic membrane sialidase, and they suggest that this enzyme may act to modulate the physical properties of the membrane [2].
• Chronic ethanol also increased the concentration of the rat brain plasma membrane sialidase protein relative to that of glyceraldehyde-3-phosphate dehydrogenase by 2.4-, 1.62- and 1.51-fold in the total brain homogenate, myelin and synaptosomal membrane fractions, respectively [4].
• Thus, our studies clearly show that chronic ethanol induced deglycosylation of brain gangliosides is in part, due to specific up-regulation of plasma membrane sialidase in the myelin and synaptosomal membrane fractions of the brain [4].
• In an attempt to understand the possible mechanism of chronic ethanol-induced generation of asialoconjugates in the brain and consequent behavioral abnormalities, we have studied the effects of chronic ethanol feeding to rats on the plasma membrane sialidase status in the various subcellular fractions of the brain [4].

Anatomical context of Neu3

• Ganglioside sialidase activity in erythrocytes (whether expressed as units/mg of protein or units/ml of blood) was 1.37- to 1.40-fold higher (p < 0.01) in the ethanol-fed group than in the control group [5].
• Chronic ethanol increases ganglioside sialidase activity in rat leukocytes, erythrocytes, and brain synaptosomes [5].
• Cerebellar granule cells in culture exhibit a ganglioside-sialidase presumably linked to the plasma membrane [6].
• These increases in plasma membrane sialidase activity and its protein content were due to concomitant increases in their relative synthetic rates by 115% (p < 0.01) and 72% (p < 0.01) in the myelin and synaptosomal membrane fractions, respectively [4].
• Intraperitoneal treatment of rat peritoneal macrophages with OK-432 results in more than 9-fold increase in the activity of ganglioside sialidase, which seems to coincide with the appearance of a cell surface antigen, asialo-GM1 [7].

Associations of Neu3 with chemical compounds

• Chronic ethanol consumption upregulates the cytosolic and plasma membrane sialidase genes, but down regulates lysosomal membrane sialidase gene in rat liver [8].
• A heavy metal ion such as Cu2+ (1 mM) and thiol-modifying 4-hydroxymercuribenzoate (50 microM) caused complete inhibition of the activities of cytosolic sialidase and membrane sialidase I, while no decrease in the activities of intralysosomal sialidase and membrane sialidase II was observed [9].

Other interactions of Neu3

• Ethanol feeding at 36% dietary calories caused an increase in the ganglioside sialidase activity of the plasma membrane sialidase (PMS) by 232% (P < .01) and that of cytosolic sialidase (CS) by 184% (P < .05), but decreased the lysosomal membrane sialidase (LMS) by 54% (P < .01) when compared with the control animals [10].

Analytical, diagnostic and therapeutic context of Neu3

• We determined the plasma membrane sialidase protein by Western blot using the anti-plasma membrane sialidase [4].

References