scholarly journals Selective hepatic uptake of synthetic glycoproteins: mannosaminated ribonuclease A dimer and serum albumin.

1979 ◽  
Vol 74 (4) ◽  
pp. 495-509 ◽  
Author(s):  
G Wilson
Keyword(s):  
Serum Albumin ◽  
Reductive Amination ◽  
Hepatic Uptake ◽  
Ribonuclease A ◽  
Liver Uptake ◽  
Lysine Residues ◽  
Minor Site ◽  
Pancreatic Ribonuclease A ◽  
A Minor ◽  
Derivatives Of

The influence of mannose-containing oligosaccharides on the tissue uptake of glycoproteins has been examined with synthetic glycoconjugates. Oligosaccharides obtained from the acetolysis of bakers' yeast mannan have been coupled to the lysine residues of the cross-linked dimer of bovine pancreatic ribonuclease A and of human serum albumin by reductive amination with cyanoborohydride. 14C-labeled derivatives of the two proteins containing two to four mannopyranose residues per 10,000 mol wt were administered intravenously to rats. There was selective (70-80%) uptake of these derivatives by the liver within 10-15 min after injection. A minor site of uptake was the spleen. The extent of hepatic uptake was a function of the number and size of the mannooligosaccharide residues coupled. With the nonglycosaminated derivatives the liver uptake was less than 5%. Related studies have shown that mannose-containing glycoproteins are taken up by both the endothelial and Kupffer cells of the liver; thus, reductive mannosamination may provide a means of directing to these cells proteins of potential therapeutic interest.

scholarly journals Clearance of circulating IgA immune complexes is mediated by a specific receptor on Kupffer cells in mice.

1984 ◽  
Vol 160 (1) ◽  
pp. 125-137 ◽  
Author(s):  
A Rifai ◽  
M Mannik
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Kupffer Cells ◽  
Immune Complexes ◽  
Serum Proteins ◽  
Hepatic Uptake ◽  
Liver Uptake ◽  
Electron Microscope Autoradiography ◽  
Iga Immune Complexes

To characterize the physiology of circulating IgA immune complexes (IgA-IC), the dynamics of IgA-IC removal by the liver were examined. After intravenous injection, covalently cross-linked IgA antibodies to the dinitrophenyl determinant were rapidly removed from the circulation by the liver. Immunofluorescence microscopy and light and electron microscope autoradiography showed that the IgA-IC were associated with Kupffer cells. With increasing doses of injected IgA-IC the clearance velocity approached a maximum, thus prolonging the circulation of IgA-IC. All these observations indicated a receptor-mediated process. Saturating doses of various potential receptor-blocking agents, heat-aggregated mouse IgG, microaggregated human serum albumin, and purified dimeric IgA did not influence the clearance pattern and hepatic uptake of radiolabeled IgA-IC. Mouse livers were also perfused via the portal vein with 1 microgram of IgA-IC. In the presence or absence of serum proteins, 43% of the perfused IgA-IC were removed in a single passage. This liver uptake was not reduced with simultaneous perfusion of large doses of aggregated mouse IgG, aggregated human serum albumin, or purified free dimeric mouse IgA. In contrast, the liver uptake of radiolabeled IgA-IC was decreased by 88% with the addition of 1 mg unlabeled IgA-IC. These observations support the conclusion that removal of IgA-IC from circulation is mediated by a specific IgA receptor on Kupffer cells.

scholarly journals Avocado-Derived Biomass: Chemical Composition and Antioxidant Potential

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 100
Author(s):  
Minerva C. García-Vargas ◽  
María del Mar Contreras ◽  
Irene Gómez-Cruz ◽  
Juan Miguel Romero-García ◽  
Eulogio Castro
Keyword(s):  
Chemical Composition ◽  
Phenolic Content ◽  
Antioxidant Properties ◽  
Total Phenolic ◽  
Nutritional Properties ◽  
Aqueous Fraction ◽  
Extraction Solvent ◽  
Main Components ◽  
A Minor ◽  
Derivatives Of

Avocado has become fashionable due to its great organoleptic and nutritional properties. It is consumed as a fresh product and it is also processed to obtain salad oil and guacamole. In all cases, the only usable portion is the pulp. Therefore, to be a more sustainable and profitable agribusiness, it is important to recognize which compounds from the peel and the stone waste can be converted into valuable bio-products. Therefore, their chemical composition was determined according to the National Renewable Energy Laboratory, the total phenolic content by the Folin-Ciocalteu method and the antioxidant properties by the FRAP and TEAC assays. The main components of the peel and stone were acid-insoluble lignin (35.0% and 15.3%, respectively), polymeric sugars (23.6% and 43.9%, respectively), and the aqueous extractives (15.5% and 16.9%, respectively). Both biomasses contain lipids and protein, but a minor proportion (<6%). The valorization of lignin and sugars is of interest given the high content; stones are a rich source of glucose (93.2% of the polymeric fraction), which could be used to obtain biofuels or derivatives of interest. The extractive fraction of the peel contained the highest number of phenolic compounds (4.7 g/100 g biomass), mainly concentrated in the aqueous fraction (i.e., 87%) compared to the ethanol one, which was subsequently extracted. It correlated with major antioxidant activity and, therefore, the peel can be applied to obtain antioxidants and water can be used as an environmentally friendly extraction solvent.

scholarly journals On the Preparation of Bovine Pancreatic Ribonuclease A

1963 ◽  
Vol 238 (2) ◽  
pp. 618-621 ◽  
Author(s):  
Arthur M. Crestfield ◽  
William H. Stein ◽  
Stanford Moore
Keyword(s):  
Ribonuclease A ◽  
Pancreatic Ribonuclease ◽  
Pancreatic Ribonuclease A

scholarly journals The Amino Acid Sequence of Ovine Pancreatic Ribonuclease A

1973 ◽  
Vol 248 (22) ◽  
pp. 7833-7837
Author(s):  
Ryoko Kobayashi ◽  
C.H.W. Hirs ◽  
With the technical assistance of Marie Hagenhuber
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Ribonuclease A ◽  
Pancreatic Ribonuclease ◽  
Pancreatic Ribonuclease A
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