The Microheterogeneity of Human Haptoglobin and Its Complex with Hemoglobin

1973 ◽  
Vol 51 (5) ◽  
pp. 597-605 ◽  
Author(s):  
H. J. Yang ◽  
M. Przybylska
Keyword(s):  
Sialic Acid ◽  
Density Gradient ◽  
Isoelectric Focusing ◽  
Acid Content ◽  
Sucrose Density Gradient ◽  
Polyacrylamide Gel ◽  
Ascites Fluid ◽  
Sialic Acid Content ◽  
Symmetrical Distribution ◽  
Complex Components

Human haptoglobin, type 1S-1S, isolated from plasma and from ascites fluid was subjected to isoelectric focusing in polyacrylamide gel and its complex with horse cyanomethemoglobin was analyzed by isoelectric focusing in a column using a sucrose density gradient. Both methods revealed microheterogeneity. Similar patterns were obtained consisting of five to eight strong bands with a symmetrical distribution giving the highest yield in the center. An investigation of the nature of these bands was carried out and it was found that the sialic acid content varied in the different components. Experiments were undertaken to show that the multiple bands were not due to the binding of Ampholine to the protein and that this heterogeneity preexisted in haptoglobin prior to its isolation. No observable difference in heterogeneity was observed between samples of haptoglobin isolated by different methods and for complexes obtained by adding hemoglobin to haptoglobin and haptoglobin to hemoglobin.The unfractionated complex and the separated complex components were crystallized.

POLAR BEAR MILK: III. GEL-ELECTROPHORETIC STUDIES OF PROTEIN FRACTIONS ISOLATED FROM POLAR BEAR MILK AND HUMAN MILK

1967 ◽  
Vol 45 (6) ◽  
pp. 1205-1210 ◽  
Author(s):  
B. E. Baker ◽  
V. B. Hatcher ◽  
C. R. Harington
Keyword(s):  
Sialic Acid ◽  
Acid Content ◽  
Polar Bear ◽  
Whey Proteins ◽  
Electrophoretic Analysis ◽  
Polyacrylamide Gel ◽  
Sialic Acid Content ◽  
Electrophoretic Patterns ◽  
Centrifuge Tube ◽  
Starch Gel

Polar bear milk was stored in the frozen state for 2 months. It was then thawed and subjected to low-speed centrifugation. The material (D) which deposited at the bottom of the centrifuge tube and also the casein and whey proteins isolated from the supernate were analyzed by polyacrylamide-gel (without urea) electrophoresis. The precipitate (D) and the casein gave closely similar electrophoretic patterns. However, the precipitate (D) contained less than 20% of the carbohydrate (hexose, hexosamine, sialic acid) content of the casein. Polar bear casein and bovine casein gave similar electropherograms when subjected to polyacrylamide-gel (7 M urea) electrophoretic analysis. Human casein gave eight distinct bands, four of which had higher mobilities than did bovine αs-casein. Starch-gel (2-mercaptoethanol added) electrophoretic analysis indicated that polar bear casein and human casein produced 8 and 13 electrophoretic components respectively.

Contribution of Sialic Acid to the Heterogeneity of Human Fibrinogen Polypeptide Chains

1979 ◽  
Author(s):  
C. Kuyas ◽  
A. Haeberli ◽  
P.W Straub
Keyword(s):  
Sialic Acid ◽  
Isoelectric Focusing ◽  
Acid Content ◽  
Polypeptide Chain ◽  
Sialic Acid Content ◽  
Human Fibrinogen ◽  
Single Donor ◽  
The Individual ◽  
Polypeptide Chains ◽  
Vibrio Cholerae Sialidase

Human fibrinogen, isolated from single donor or from pooled plasma, shows a heterogeneity of the Bऔ- and the γ-polypeptide chains on CM-cellulose chromatography. In order to find out whether this heterogeneity is due to the observed differences in sialic acid content of the variants (2 and 1 residue per chain; Gati et al., J.Biol.Chem.253:1315,1978) pooled or single donor fibrinogen (clottability 93-95%) was incubated 24 hrs with either vibrio cholerae sialidase or buffer. The asialofibrinogen (10% of original sialic acid) was compared with intact fibrinogen. After dithiothreitol reduction and alkylation the chains were separated on CM Sepharose. The individual homogeneous Bऔ- and γ-chains were rechromatographed on CM-cellulose. The γ-chain heterogeneity of normal fibrinogen was absent in asialofibrinogen whereas the Bऔ-chain heterogeneity appeared unaffected. Although the variants were indistinguishable on SOS-PAGE, isoelectric focusing in presence of urea demonstrated heterogeneities of both Bऔ- and γ-chains even in asialofibrinogen. Thus, the differences in sialic acid content of the main polypeptide chain variants of pooled as wel l as single donor human fibrinogen can only explain a small part of the polypeptide chain heterogeneity.

Dual activity of human pituitary thyrotrophin isoforms on thyroid cell growth

1994 ◽  
Vol 13 (2) ◽  
pp. 187-198 ◽  
Author(s):  
G Medri ◽  
I Sergi ◽  
M-J Papandréou ◽  
P Beck-Peccoz ◽  
B Verrier ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Sialic Acid ◽  
Cell Growth ◽  
Isoelectric Focusing ◽  
Acid Content ◽  
Thyroid Cell ◽  
Camp Production ◽  
Con A ◽  
Sialic Acid Content ◽  
Neuraminidase Treatment

ABSTRACT Alkaline (pI 8·6–7·5) and neutral (pI 7·0–6·0) isoforms of human TSH have been isolated from a highly purified intrapituitary preparation by isoelectric focusing and compared for their respective actions on thyroid cell proliferation. Both TSH isoforms displayed the same ability to bind to porcine thyroid membranes as the original hormone preparation, indicating a similar recognition at the receptor sites. Alkaline forms showed a higher potency in inducing either cyclic AMP (cAMP) production or [3H]thymidine incorporation in FRTL-5 cells (half-maximal effective doses (ED50 values)=0·25 and 0·29 nm respectively) compared with their neutral counterparts (ED50 values=0·66 and 0·70 nm respectively). Increasing the concentration of alkaline forms in the presence of a half-maximal concentration of neutral TSH resulted in a profound inhibition of cell growth without a significant change in cAMP. Conversely, increasing the amount of neutral forms in the presence of a half-maximal dose of alkaline TSH resulted in an additive response for cAMP production but not in cell proliferation. To assess whether glycosylation might be responsible for the variation in hormone action, both alkaline and neutral TSH isoforms were tested for recognition of their carbohydrate chains by concanavalin A (Con A) and ricin. No major difference was found in binding to Con A, indicating that the contribution of carbohydrates to changes in hormone pI was not related to core branching. Very few galactose residues were accessible in either hormone fraction since little binding to ricin was observed. Isoelectric focusing of TSH forms before and after neuraminidase treatment revealed that neutral forms had a higher sialic acid content than alkaline TSH. In conclusion, the current findings show that TSH isoforms differentially affect cAMP production and cell growth. TSH fractions with a high sialic acid content and a low mitogenic activity behave as antagonists to the more active forms for cell proliferation. It is suggested that physiological control of TSH action at the thyroid gland may reside in the respective amounts of various TSH forms which, once bound to their receptor, can induce variable activation of post-receptor events while controlling cell proliferation.

129: Sialic Acid Content of Urinary TAMM-Horsfall Protein is Reduced in Interstitial Cystitis Patients

2007 ◽  
Vol 177 (4S) ◽  
pp. 44-45
Author(s):  
C. Lowell Parsons ◽  
Mahadevan Rajasekaran ◽  
Marianne Chenoweth ◽  
Paul Stein
Keyword(s):  
Sialic Acid ◽  
Interstitial Cystitis ◽  
Acid Content ◽  
Sialic Acid Content

scholarly journals Differences in Sialic Acid Content of Human Interferons

1978 ◽  
Vol 41 (1) ◽  
pp. 175-178 ◽  
Author(s):  
J. Morser ◽  
J. P. Kabayo ◽  
D. W. Hutchinson
Keyword(s):  
Sialic Acid ◽  
Acid Content ◽  
Sialic Acid Content

scholarly journals Infection with Listeria monocytogenes impairs sialic acid addition to host cell glycoproteins.

1994 ◽  
Vol 180 (6) ◽  
pp. 2137-2145 ◽  
Author(s):  
M S Villanueva ◽  
C J Beckers ◽  
E G Pamer
Keyword(s):  
Listeria Monocytogenes ◽  
Sialic Acid ◽  
Host Cell ◽  
Mhc Class I ◽  
Acid Content ◽  
Class I ◽  
Sialic Acid Content ◽  
Infected Cells ◽  
The Impact ◽  
Glycosylation Defect

Listeria monocytogenes is a facultative intracellular bacterium that causes severe disease in neonates and immunocompromised adults. Although entry, multiplication, and locomotion of Listeria in the cytosol of infected cells are well described, the impact of such infection on the host cell is unknown. In this report, we investigate the effect of L. monocytogenes infection on MHC class I synthesis, processing, and intracellular trafficking. We show that L. monocytogenes infection interferes with normal processing of N-linked oligosaccharides on the major histocompatibility complex (MHC) class I heavy chain molecule, H-2Kd, resulting in a reduced sialic acid content. The glycosylation defect is more pronounced as the infection progresses and results from interference with the addition of sialic acid rather than its removal by a neuraminidase. The effect is found in two different cell lines and is not limited to MHC class I molecules since CD45, a surface glycoprotein, and LGP120, a lysosomal glycoprotein, are similarly affected by L. monocytogenes infection. The glycosylation defect is specific for infection by L. monocytogenes since neither Trypanosoma cruzi nor Yersinia enterocolitica, two other intracellular pathogens, reproduces the effect. The resultant hyposialylation of H-2Kd does not impair its surface expression in infected cells. Diminished sialic acid content of surface glycoproteins may enhance host-defense by increasing susceptibility to lysis and promoting clearance of Listeria-infected cells.

scholarly journals Erythrocyte Sialic Acid Content during Aging in Humans: Correlation with Markers of Oxidative Stress

2012 ◽  
Vol 32 (3) ◽  
pp. 179-186 ◽  
Author(s):  
Mohammad Murtaza Mehdi ◽  
Prabhakar Singh ◽  
Syed Ibrahim Rizvi
Keyword(s):  
Oxidative Stress ◽  
Sialic Acid ◽  
Erythrocyte Membrane ◽  
Acid Content ◽  
Lipid Hydroperoxide ◽  
Plasma Lipid ◽  
Sialic Acids ◽  
Sialic Acid Content ◽  
Total Antioxidant ◽  
The Relationship

Sialic acids are substituted neuraminic acid derivatives which are typically found at the outermost end of glycan chains on the membrane in all cell types. The role of erythrocyte membrane sialic acids during aging has been established however the relationship between sialic acid and oxidative stress is not fully understood. The present work was undertaken to analyze the relationship between erythrocyte membrane sialic acid with its plasma level, membrane and plasma lipid hydroperoxide levels and plasma total antioxidant capacity. Results show that sialic acid content decreases significantly (P< 0.001) in RBC membrane (r= −0.901) and increases in plasma (r= 0.860) as a function of age in humans. Lipid peroxidation measured in the form of hydroperoxides increases significantly (P< 0.001) in plasma (r= 0.830) and RBC membranes (r= 0.875) with age in humans. The Trolox Equivalent Total Antioxidant Capacity (TETAC) of plasma was found to be significantly decreased (P< 0.001,r= −0.844). We observe significant correlations between decrease of erythrocyte membrane sialic acid and plasma lipid hydroperoxide and TETAC. Based on the observed correlations, we hypothesize that increase in oxidative stress during aging may influence the sialic acid decomposition from membrane thereby altering the membrane configuration affecting many enzymatic and transporter activities. Considering the importance of plasma sialic acid as a diagnostic parameter, it is important to establish age-dependent reference.

Tamm-Horsfall glycoprotein: role in inhibition and promotion of renal calcium oxalate stone formation studied with Fourier-transform infrared spectroscopy

1994 ◽  
Vol 40 (9) ◽  
pp. 1739-1743 ◽  
Author(s):  
R Knörle ◽  
P Schnierle ◽  
A Koch ◽  
N P Buchholz ◽  
F Hering ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Sialic Acid ◽  
Calcium Oxalate ◽  
Fourier Transform Infrared Spectroscopy ◽  
Acid Content ◽  
Stone Formation ◽  
Fourier Transform Infrared ◽  
Sialic Acid Content ◽  
Stone Formers

Abstract Tamm-Horsfall glycoprotein (THP) from healthy probands inhibits the precipitation of calcium oxalate, whereas THP from individuals who repeatedly develop calcium oxalate stones has no effect or even promotes precipitation. Using Fourier-transform infrared spectroscopy, we found a structural differentiation between these functionally different THPs: a decisive difference in sialic acid content. Quantitative analysis for sialic acid showed the same results. THP from healthy probands had a high sialic acid content (51 +/- 9 g/kg), whereas THP from recurrent stone formers had a decreased sialic acid content (21 +/- 4 g/kg). This explains the dual role of THP in the precipitation of calcium oxalate and the formation of renal stones and shows the importance of glycosylation in the function of this glycoprotein.

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