Degradation of Glycoproteins

Patel, Vimalkumar

doi:10.1016/b978-0-12-356102-2.50011-1

Cited by 4 publications

(1 citation statement)

References 292 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inherited defects in the catabolism of complex glycoconjugates may lead in many cases to a clinical course involving, among other symptoms, neurovisceral degeneration and mental retardation. Such defects present themselves biochemically with the accumulation of large concentrations of oligosaccharides, glycosphingolipids, or glycosaminoglycans in the lysosomes and in the hyperexcretion of the corresponding oligosaccharides and glycosaminoglycans in the urine (Dawson, 1978;Patel, 1978).…”

mentioning

confidence: 99%

Generalized N‐Acetylneuraminic Acid Storage Disease: Quantitation and Identification of the Monosaccharide Accumulating in Brain and Other Tissues

Hancock¹,

Thaler²,

Horwitz³

et al. 1982

Journal of Neurochemistry

View full text Add to dashboard Cite

Brain and other tissues from a patient with extensive neonatal ascites and clinical symptoms suggestive of a severe neurovisceral storage disorder were examined following autopsy for the accumulation of oligosaccharides. This carbohydrate analysis revealed the presence of large amounts (3--21) mumol/g fresh weight) of sialic acid in brain, liver, and kidney tissue as the major abnormality. Exhaustive characterization of the accumulating material by gel filtration, gas-liquid chromatography, thin-layer chromatography, and GLC-mass spectrometry positively identified the saccharide as free N-acetylneuraminic acid. Based on the accumulation of only free N-acetylneuraminic acid in the tissue of this patient, and normal activities of lysosomal enzymes involved in the catabolism of cellular glycoproteins, this storage disorder appears to result from a previously unreported defect in glycoconjugate metabolism.

show abstract

mentioning

confidence: 99%

Generalized N‐Acetylneuraminic Acid Storage Disease: Quantitation and Identification of the Monosaccharide Accumulating in Brain and Other Tissues

Hancock¹,

Thaler²,

Horwitz³

et al. 1982

Journal of Neurochemistry

View full text Add to dashboard Cite

show abstract

Structure and Metabolism of Connective Tissue Proteoglycans

Rodén

1980

The Biochemistry of Glycoproteins and Proteoglycans

251

107

View full text Add to dashboard Cite

Rat‐liver lysosomal sialidase

Miyagi

Tsuiki

1984

European Journal of Biochemistry

109

View full text Add to dashboard Cite

Purified liver lysosomes, prepared from rats previously injected with Triton WR-1339, exhibited sialidase activity towards sialyllactose, fetuin, submaxillary mucin (bovine) and gangliosides, and could be disrupted hypotonically with little loss in these activities. After centrifugation, the activities with sialyllactose and fetuin were largely recovered in the supernatant, demonstrating that they were originally in the intralysosomal space. The activities towards submaxillary mucin and gangliosides, on the other hand, remained in the pellet. In the supernatant, activity with fetuin or orosomucoid was markedly reduced by protease inhibitors, suggesting that proteolysis of these glycoproteins may be prerequisite to sialidase activity.The intralysosomal sialidase was solubilized from the mitochondrial-lysosomal fraction of rat liver and partially purified by Sephadex G-200, or Sephadex G-200 followed by CM-cellulose. The enzyme was maximally active at pH 4.7 with sialyllactose as substrate and had a minimum relative molecular mass of 60000 k 5000 by gel filtration; it hydrolyzed a variety of sialooligosaccharides, those containing (a2+ 3)sialyl linkages being better substrates than those with (a2+6)sialyl linkages. The enzyme failed to attack submaxillary mucin and gangliosides. It was also inactive towards fetuin, orosomucoid and transferrin but capable of hydrolyzing glycopeptides from pronase digest of fetuin.In contrast to the intralysosomal silaidase, the sialidase partially purified from rat liver cytosol by (NH,),SO, fractionation followed by chromatography on DEAE-cellulose and CM-cellulose hydrolyzed fetuin and orosomucoid to the extent about half that for sialyllactose. The enzyme was maximally active at pH 5.8 and had a relative molecular mass of approximately 60000. It also hydrolyzed gangliosides but not submaxillary mucin.

show abstract

Degradation of Glycoproteins

Cited by 4 publications

References 292 publications

Generalized N‐Acetylneuraminic Acid Storage Disease: Quantitation and Identification of the Monosaccharide Accumulating in Brain and Other Tissues

Generalized N‐Acetylneuraminic Acid Storage Disease: Quantitation and Identification of the Monosaccharide Accumulating in Brain and Other Tissues

Structure and Metabolism of Connective Tissue Proteoglycans

Rat‐liver lysosomal sialidase

Contact Info

Product

Resources

About