scholarly journals Release of intestinal surface-membrane glycoproteins associated with enzyme activity by brief digestion with papain

1971 ◽  
Vol 121 (5) ◽  
pp. 781-789 ◽  
Author(s):  
Gordon G. Forstner

Rat intestinal surface-membrane glycoproteins were labelled by intraperitoneal injection of [1-14C]glucosamine 4h before the animals were killed. At this time, density-gradient centrifugation of disrupted brush borders indicated that glycoprotein radioactivity was distributed identically with sucrase, a plasma-membrane marker. Labelled brush borders were digested by papain for brief time-intervals known to release surface-enzyme particles without disruption of the unit membrane. Digestion for 5min released 90% of the surface sucrase, and almost one-half of the brush-border glycoprotein and label. On Sepharose 4B column chromatography most of the glycoprotein and label emerged as a single peak. This peak contained the most actively labelled glycoprotein in the brush border and was closely associated with maltase, sucrase, β-naphthylamidase and alkaline phosphatase. The peak was partially resolved on polyacrylamide-gel electrophoresis into three bands. Each band contained a distinctive enzyme or enzyme pair, and was labelled by [1-14C]glucosamine. No periodic acid–Schiff-negative protein was observed in the peak material. Glycoproteins susceptible to brief digestion with papain are therefore closely linked to released surface-enzyme particles. Intestinal surface glycoproteins are heterogeneous with respect to molecular weight, electrophoretic mobility and function.

Blood ◽  
1982 ◽  
Vol 59 (4) ◽  
pp. 709-718 ◽  
Author(s):  
AT Nurden ◽  
TJ Kunicki ◽  
D Dupuis ◽  
C Soria ◽  
JP Caen

Abstract The gray platelet syndrome is a rare inherited platelet disorder characterized by the absence of alp ha-granules as observed by electron microscopy. Analysis of the glycoprotein composition of the platelets of 2 such patients by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed decreased or absent staining for carbohydrate of several high molecular weight glycoproteins. The major periodic acid Schiff (PAS) staining membrane glycoproteins were normally detected and were normally labeled with 125I during lactoperoxidase-catalyzed iodination. Analysis of the protein composition of gray platelets by single or two- dimensional SDS-PAGE followed by Coomassie blue staining revealed an apparent absence of GP Ig (thrombospondin), markedly reduced platelet fibrinogen and albumin concentrations, and severely reduced levels of 2 low molecular weight polypeptides exhibiting identical rates of migration on SDS-PAGE as platelet factor 4 and beta-thromboglobulin. SDS-PAGE profiles similar to those of the gray platelets were observed with normal human platelets that had undergone the release reaction induced by thrombin. Analysis of gray platelet proteins by crossed immunoelectrophoresis using a rabbit anti-human platelet antibody preparation and rocket immunoelectrophoresis using monospecific antisera confirmed the above findings and showed additional severe deficiencies of factor VIIIR:Ag and cold-insoluble globulin. In contrast, factor XIII (subunit A), a cytoplasmic protein, was normally detected. Our studies provide further evidence that circulating gray platelets specifically lack, or have markedly decreased concentrations of, the alpha-granule proteins.


1982 ◽  
Vol 201 (2) ◽  
pp. 287-295 ◽  
Author(s):  
Ian A. King ◽  
Anne Tabiowo

1. Non-desmosomal plasma membranes enriched in plasma-membrane marker enzymes and in metabolically labelled glycoproteins were isolated on a large scale from up to 500g of pig ear skin slices. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and periodic acid/Schiff staining revealed the presence of four major glycosylated components in the apparent molecular-weight range 150000–80000. 2. A large proportion of the marker enzymes, the d-[3H]glucosamine-labelled glycoproteins and the periodic acid/Schiff-stained glycoproteins were solubilized by 1% (w/v) sodium deoxycholate. However, several non-glycosylated proteins, in particular those with mol.wts. 81000, 41000 and 38000 (possibly cytoskeletal components), were relatively resistant to solubilization. 3. The deoxycholate-solubilized membranes were fractionated by lectin affinity chromatography using both concanavalin A–Sepharose 4B and lentil lectin–Sepharose 4B. From 75 to 85% of the applied glycoprotein was recovered from the columns. From 30 to 40% of the recovered glycoprotein was specifically bound by the lectins and was eluted with 2% (w/v) α-methyl d-mannoside. The enrichment of labelled glycoproteins in the material bound by the lectins (2.5-fold) was similar with both lectins, although the yield was somewhat greater when lentil lectin was used. The glycoprotein-enriched fraction was also enriched in all the plasma-membrane marker enzymes, indicating their probable glycoprotein nature. 4. The glycoprotein-enriched fraction contained the four major periodic acid/Schiff-stained bands that were detected in the original plasma membrane. They had apparent mol.wts. 147000, 130500, 108000 and 91400. The higher-molecular-weight components contained relatively more d-[3H]glucosamine, indicating differences in the sugar composition or in the metabolic turnover of the individual glycoproteins in culture. The material bound by the lectins also contained a number of lower-molecular-weight Coomassie Brilliant Blue-stained components. These were weakly stained by periodic acid/Schiff reagent and were lightly labelled with d-[3H]glucosamine, indicating that they contained less carbohydrate than the four major glycoprotein bands. 5. Chloroform/methanol-extracted plasma membranes and isolated glycoproteins had a similar carbohydrate composition, containing sialic acid, hexosamine, fucose, xylose, mannose, galactose and glucose. Glucose was not enriched in the isolated glycoproteins, suggesting that it may be a contaminant. Xylose, however, was enriched in the isolated glycoproteins. It remains to be established whether this sugar, which is not usually found in plasma-membrane glycoproteins, is a genuine constituent of plasma-membrane glycoproteins in the epidermis.


Blood ◽  
1982 ◽  
Vol 59 (4) ◽  
pp. 709-718 ◽  
Author(s):  
AT Nurden ◽  
TJ Kunicki ◽  
D Dupuis ◽  
C Soria ◽  
JP Caen

The gray platelet syndrome is a rare inherited platelet disorder characterized by the absence of alp ha-granules as observed by electron microscopy. Analysis of the glycoprotein composition of the platelets of 2 such patients by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed decreased or absent staining for carbohydrate of several high molecular weight glycoproteins. The major periodic acid Schiff (PAS) staining membrane glycoproteins were normally detected and were normally labeled with 125I during lactoperoxidase-catalyzed iodination. Analysis of the protein composition of gray platelets by single or two- dimensional SDS-PAGE followed by Coomassie blue staining revealed an apparent absence of GP Ig (thrombospondin), markedly reduced platelet fibrinogen and albumin concentrations, and severely reduced levels of 2 low molecular weight polypeptides exhibiting identical rates of migration on SDS-PAGE as platelet factor 4 and beta-thromboglobulin. SDS-PAGE profiles similar to those of the gray platelets were observed with normal human platelets that had undergone the release reaction induced by thrombin. Analysis of gray platelet proteins by crossed immunoelectrophoresis using a rabbit anti-human platelet antibody preparation and rocket immunoelectrophoresis using monospecific antisera confirmed the above findings and showed additional severe deficiencies of factor VIIIR:Ag and cold-insoluble globulin. In contrast, factor XIII (subunit A), a cytoplasmic protein, was normally detected. Our studies provide further evidence that circulating gray platelets specifically lack, or have markedly decreased concentrations of, the alpha-granule proteins.


1986 ◽  
Vol 60 (5) ◽  
pp. 1615-1622 ◽  
Author(s):  
S. Yanagawa ◽  
H. Yokozeki ◽  
K. Sato

To evaluate the possible involvement of ductal blockade with periodic acid-Schiff (PAS)-positive materials in the mechanism of hidromeiosis in humans, skin slices were incubated with methacholine for 2 h and PAS-positive materials localized histologically in the ductal lumen. In 20% of the glands complete ductal blockade with PAS-positive materials was noted. The characteristics and origin of such PAS-positive glycoproteins in human sweat were then studied using various electrophoretic techniques. One-dimensional sodium dodecylsulfate-polyacrylamide gel electrophoresis (1-D SDS-PAGE) demonstrated considerable individual variation in the electrophoretic pattern; however, four major bands at 45, 28, 20, and 18K shared by different individuals, were PAS positive. Further studies using two-dimensional SDS-PAGE, immunodiffusion and immunoaffinity chromatography demonstrated that the PAS-positive glycoproteins are not derived directly from serum because they are electrophoretically and antigenically distinct from serum proteins, including alpha 1-glycoprotein, alpha 2-HS-glycoprotein, and alpha 1-antitrypsin. Since only dark cell granules are densely stained in the histochemical PAS staining, and because antiserum produced against the PAS-positive band selectively stained cells facing the secretory coil lumen (which are most likely dark cells), it is suggested that PAS-positive sweat glycoproteins are derived predominantly from the dark cells.


1981 ◽  
Vol 195 (2) ◽  
pp. 389-397 ◽  
Author(s):  
D A Wiginton ◽  
M S Coleman ◽  
J J Hutton

Adenosine deaminase was purified 3038-fold to apparent homogeneity from human leukaemic granulocytes by adenosine affinity chromatography. The purified enzyme has a specific activity of 486 mumol/min per mg of protein at 35 degrees C. It exhibits a single band when subjected to sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, non-denaturing polyacrylamide-gel electrophoresis and isoelectric focusing. The pI is 4.4. The enzyme is a monomeric protein of molecular weight 44000. Both electrophoretic behaviour and molecular weight differ from those of the low-molecular-weight adenosine deaminase purified from human erythrocytes. Its amino acid composition is reported. Tests with periodic acid-Schiff reagent for associated carbohydrate are negative. Of the large group of physiological compounds tested as potential effectors, none has a significant effect. The enzyme is specific for adenosine and deoxyadenosine, with Km values of 48 microM and 34 microM respectively. There are no significant differences in enzyme function on the two substrates. erythro-9-(2-Hydroxy non-3-yl) adenine is a competitive inhibitor, with Ki 15 nM. Deoxycoformycin inhibits deamination of both adenosine and deoxyadenosine, with an apparent Ki of 60-90 pM. A specific antibody was developed against the purified enzyme, and a sensitive radioimmunoassay for adenosine deaminase protein is described.


1981 ◽  
Author(s):  
A K Rao ◽  
G P Tuszynski ◽  
L Knight ◽  
J Willis ◽  
C Beckett

Platelets stored as concentrates (PC) at 22° C for 72 hours develop a functional defect in vitro tests. Alterations in membrane glycoproteins of platelets have been shown to effect platelet function. We have investigated the effect of storage on membrane glycoproteins (GP) and cytoskeletons (cyto.) of platelets. Gel filtered platelets from fresh PC were labeled with 125Iodine by Iodogen technique and gel filtered again to remove free iodide. Platelets were concentrated by albumin density gradient centrifugation, resuspended in autologous plasma and stored for 72 hours at 22° C. Aliquots of fresh and stored PC were solubilized with 2% sodium dodecyl sulphate (SDS) containing 5% mercaptoethanol and subjected to polyacrylamide gel electrophoresis (PAGE). In one experiment, separate aliquots of fresh and stored platelets were labeled and similarly analyzed. Gels were stained with Coomassie blue and subjected to autoradiography. Coomassie blue staining did not reveal major differences between fresh and stored platelets. Autoradiography revealed a decrease in the 170,000 dalton surface protein (GP-I) of platelets after storage. Triton insoluble cyto. of thrombin activated fresh and stored platelets were solubilized with SDS and analyzed by PAGE and autoradiography. Cytoskeletons from fresh PC revealed the presence of a 110,000 dalton surface protein (GP-III). However, cyto. from similarly treated stored platelets showed a markedly decreased amount of this protein. Thus stored platelets have decreased amounts of the 170,000 dalton surface protein (GP-I) along with decreased amounts of the 110,000 dalton protein (GP-III) associated with the cyto. of thrombin activated platelets. These changes may contribute to the functional defect reported in stored platelets.


Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 472
Author(s):  
Richard Marchal ◽  
Thomas Salmon ◽  
Ramon Gonzalez ◽  
Belinda Kemp ◽  
Céline Vrigneau ◽  
...  

Botrytis cinerea is a fungal pathogen responsible for the decrease in foamability of sparkling wines. The proteolysis of must proteins originating from botrytized grapes is well known, but far less information is available concerning the effect of grape juice contamination by Botrytis. The impact from Botrytis on the biochemical and physico-chemical characteristics of proteins released from Saccharomyces during alcoholic fermentation remains elusive. To address this lack of knowledge, a model grape juice was inoculated with three enological yeasts with or without the Botrytis culture supernatant. Size exclusion chromatography coupled to multi-angle light scattering (SEC-MALLS) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques (AgNO3 and periodic acid Schiff staining) was used in the study. When Botrytis enzymes were present, a significant degradation of the higher and medium MW molecules released by Saccharomyces was observed during alcoholic fermentation whilst the lower MW fraction increased. For the three yeast strains studied, the results clearly showed a strong decrease in the wine foamability when synthetic musts were inoculated with 5% (v/v) of Botrytis culture due to fungus proteases.


1985 ◽  
Vol 162 (1) ◽  
pp. 245-267 ◽  
Author(s):  
T W Huang ◽  
J C Langlois

A new cell surface protein, podoendin, has been identified in Sprague-Dawley rats, and isolated using monoclonal antibody (mAb) G4. The distribution of podoendin is restricted to the surface of glomerular podocytes, urinary surface of the parietal epithelium of Bowman's capsule, and the luminal surface of endothelial cells. The antibody does not crossreact with podocytes or endothelia of human or mice. In newborn rats, the appearance of podoendin on glomerular epithelium is attendant on podocyte differentiation during glomerulogenesis of metanephrogenic vesicles. It disappears when podocytes retract and efface foot processes in tissue culture. Thus, podoendin appears to be a cell differentiation-dependent surface protein of podocytes. Podoendin is a protein of 62 kD mobility on 5% polyacrylamide gel electrophoresis. It stains intensely with Coomassie blue, but gives negative reactions to carbohydrate (periodic acid/Schiff reaction) and polyanions (alcian blue, colloidal iron, and carbocyanine). It is distinct from the major sialoglycoprotein of podocyte fuzzy coat, podocalyxin (11). Podoendin isolated and purified from endothelium of lungs appears to be identical with that from podocytes and endothelium of kidneys. Injection of mAb G4 into left ventricle of rats resulted in intense decoration of the endothelium and podocyte surface within 30 min. The decoration persisted throughout the 3-d period of observation. This was not accompanied by complement (C3) fixation. Preliminary results showed that the rats developed moderate proteinuria (100 mg/ml protein in urine), which was associated with the presence of hyaline droplets in renal tubules, on the third day. The proteinuria was not accompanied by effacement of podocyte pedicels. There were no morphologic alterations indicating glomerular or vascular injury in the kidneys.


2006 ◽  
Vol 3 (3) ◽  
pp. 183-188 ◽  
Author(s):  
Tang Xin-Yan ◽  
Zeng Wei-Dong ◽  
Mi Yu-Ling ◽  
Liu Hong-Yun ◽  
Zhang Cai-Qiao

AbstractPrimordial germ cells (PGCs) were isolated from the genital ridges of chicken (Gallus domesticus) embryos at the 19th stage and purified by Ficoll density-gradient centrifugation. PGCs were co-cultured with somatic cells in preliminary culture and subcultured. Identification of PGCs was carried out by histochemical methods, including alkaline phosphatase (AKP) and periodic acid–Schiff (PAS). The proliferating activity of PGCs in subculture was demonstrated by immunocytochemistry of proliferating cell nuclear antigen (PCNA). Meanwhile, proliferating PGCs were compared under different culture conditions of 5–20% fetal cattle serum (FCS), insulin–transferrin–selenite (ITS) medium, conditioned medium (CM), 15% FCS+ITS, 15% FCS+40% CM. The results showed that the cultured PGCs were positive for AKP and PAS staining and displayed intensive proliferating activity by PCNA. The PGCs without centrifugation grew better than those with centrifugation. The PGCs formed larger colonies in media with 5% FCS or ITS than other media, indicating that 5% FCS or ITS supplemented media could be an ideal culture system for PGC proliferation in the PGC-somatic cell co-culture, in addition to the embryonic fibroblast feeder layer.


1968 ◽  
Vol 52 (3) ◽  
pp. 482-494 ◽  
Author(s):  
Robert G. Faust ◽  
Mary G. Leadbetter ◽  
Regina K. Plenge ◽  
Alston J. McCaslin

Tris-disrupted and intact brush border membrane preparations from mucosa of hamster jejunum were capable of preferentially binding actively transported D-glucose in a similar manner. Density gradient centrifugation of the Tris-disrupted brush borders indicated that D-glucose was bound to a fraction containing the cores or inner material of the microvilli. The properties of this binding were examined with the Tris-disrupted brush border preparation. Actively transported sugars competitively inhibited preferential D-glucose binding, whereas no effect was observed with nonactively transported sugars. Neither actively nor nonactively transported amino acids affected D-glucose binding. D-Glucosamine, which is not actively transported, was inhibitory to preferential D-glucose binding as well as to the active transport of D-glucose by everted sacs of hamster jejunum. No inhibitory effect was observed with the same concentration of D-galactosamine. Preferential D-glucose binding was also inhibited by sulfhydryl-reacting compounds, Ca2+, and Li+ ions. On the other hand, Mg2+ was shown to be stimulatory and Na+, NH4+, and K+ had no effect on this phenomenon. The results of these experiments suggest that preferential D-glucose binding to brush borders is related to the initial step in active sugar transport by the small intestine.


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